diff --git a/Documentation/Changelog.md b/Documentation/Changelog.md
index b42326438..c1009cf2b 100644
--- a/Documentation/Changelog.md
+++ b/Documentation/Changelog.md
@@ -6,32 +6,45 @@
 
 ### `tdw` module
 
+- Added required modules: `pyinstaller` and `keyboard`
+- Added `tdw.keyboard_controller` A controller that can listen to keyboard input.
+
 #### `Controller`
 
 - Removed optional `display` parameter. It doesn't actually work; Linux users should instead launch the controller with a `DISPLAY` environment variable.
 
-### Frontend
-
-- Added `freeze.py`. "Freeze" your controller into a portable binary executable.
-
 #### Backend
 
-- Added `controller.spec` (used for freezing controller code).
 - Adjusted how Flatbuffers imports numpy so that frozen controller code works.
 
+### Example Controllers
+
+- Renamed `keyboard.py` to `keyboard_controller.py` to avoid a name clash with the `keyboard` module. Rewrote the code to use the `KeyboardController` class.
+
+### Build
+
+- Fixed: Segmentation colors are often non-unique.
+
+### Misc.
+
+- Added `freeze.py`. "Freeze" your controller into a portable binary executable.
+  - Added `controller.spec` (used for freezing controller code).
+
 ### Documentation
 
 #### New Documentation
 
-| Document    | Description                                                  |
-| ----------- | ------------------------------------------------------------ |
-| `freeze.md` | How to freeze your controller code into a binary executable. |
+| Document                 | Description                                                  |
+| ------------------------ | ------------------------------------------------------------ |
+| `freeze.md`              | How to freeze your controller code into a binary executable. |
+| `keyboard_controller.md` | API for KeyboardController.                                  |
 
 #### Modified Documentation
 
 | Document             | Description                                                |
 | -------------------- | ---------------------------------------------------------- |
 | `getting_started.md` | Fixed instructions for how to start a controller in Linux. |
+| `docker.md`          | Fixed some broken links.                                   |
 
 ## v1.6.4
 
diff --git a/Documentation/Docker/docker.md b/Documentation/Docker/docker.md
index 42c776259..8e82f5370 100644
--- a/Documentation/Docker/docker.md
+++ b/Documentation/Docker/docker.md
@@ -60,7 +60,7 @@ All Docker-related bash scripts are in [`tdw/Docker`](https://github.com/threedw
 | ------------------------------------------------------------ | ------------------------------------------------------------ | ------------------------------------------------------------ |
 | [`start_container.sh`](https://github.com/threedworld-mit/tdw/tree/master/Docker/start_container.sh) |                                                              | Start the container and run TDW.                             |
 | [`start_container_xpra.sh`](https://github.com/threedworld-mit/tdw/tree/master/Docker/start_container_xpra.sh) |                                                              | Start the container with [Xpra](../misc_frontend/xpra.md) and run TDW. |
-| [`start_container_audio_video.sh VOLUME IPADDRESS PORT`](https://github.com/threedworld-mit/tdw/tree/master/Docker/start_container_audio.sh) | `VOLUME` Save audio to this volume<br>`IPADDRESS` The address of the build.<br>`PORT` The port of the build. | [Record audio and video](../misc_frontend/video.md) from TDW. |
+| [`start_container_audio_video.sh VOLUME IPADDRESS PORT`](https://github.com/threedworld-mit/tdw/tree/master/Docker/start_container_audio_video.sh) | `VOLUME` Save audio to this volume<br>`IPADDRESS` The address of the build.<br>`PORT` The port of the build. | [Record audio and video](../misc_frontend/video.md) from TDW. |
 
 ### Other scripts
 
@@ -69,7 +69,7 @@ All Docker-related bash scripts are in [`tdw/Docker`](https://github.com/threedw
 | [`pull.sh`](https://github.com/threedworld-mit/tdw/tree/master/Docker/pull.sh) |                                                              | Try to download a Docker container from DockerHub with a tag that matches the version of TDW on this machine. |
 | [`docker_tag.sh`](https://github.com/threedworld-mit/tdw/tree/master/Docker/docker_tag.sh) |                                                              | Get the tag of the TDW Docker image.                         |
 | [`tdw_version.py`](https://github.com/threedworld-mit/tdw/tree/master/Docker/tdw_version.py) |                                                              | Get the version of TDW on this machine.                      |
-| [`record_audio_video.sh ADDRESS PORT WIDTH HEIGHT`](https://github.com/threedworld-mit/tdw/tree/master/Docker/record_audio.sh) | `ADDRESS` The network address of the build.<br>`PORT` The network port of the build<br> `WIDTH` The desired width of the video in pixels.<br>`HEIGHT` The desired height of the video in pixels. | Launch TDW and begin recording audio.                        |
+| [`record_audio_video.sh ADDRESS PORT WIDTH HEIGHT`](https://github.com/threedworld-mit/tdw/tree/master/Docker/record_audio_video.sh) | `ADDRESS` The network address of the build.<br>`PORT` The network port of the build<br> `WIDTH` The desired width of the video in pixels.<br>`HEIGHT` The desired height of the video in pixels. | Launch TDW and begin recording audio.                        |
 
 
 ## Docker within Docker
diff --git a/Documentation/python/example_controllers.md b/Documentation/python/example_controllers.md
index f0a3bca1a..4c0a47f55 100644
--- a/Documentation/python/example_controllers.md
+++ b/Documentation/python/example_controllers.md
@@ -23,7 +23,7 @@ Each TDW release includes many example controllers. They can be found in: `<root
 | `getting_started.py` | 1. Add a table and place an object on the table.<br>2. Add a camera and receive an image. |
 | `hdri.py` | Create an object and avatar and capture images of the scene, rotating the HDRI skybox by 15 degrees<br>for each image. |
 | `impact_sounds.py` | - Listen for collisions between objects.<br>- Generate an impact sound with py_impact upon impact and play the sound in the build. |
-| `keyboard.py` | Use WASD or arrow keys to move an avatar. |
+| `keyboard_controls.py` | Use WASD or arrow keys to move an avatar. |
 | `local_object.py` | Create a local asset bundle and load it into TDW.<br><br>See `Documentation/misc_frontend/add_local_object.md` for how to run the Asset Bundle Creator. |
 | `minimal.py` | A minimal example of how to connect to the build and receive data. |
 | `minimal_remote.py` | A minimal example of how to use the launch binaries daemon to<br>start and connect to a build on a remote node. Note: the remote<br>must be running launch_binaries.py. |
diff --git a/Documentation/python/keyboard_controller.md b/Documentation/python/keyboard_controller.md
new file mode 100644
index 000000000..7d6818f3d
--- /dev/null
+++ b/Documentation/python/keyboard_controller.md
@@ -0,0 +1,78 @@
+# `keyboard_controller.py`
+
+## `KeyboardController(Controller)`
+
+`from tdw.keyboard_controller import KeyboardController`
+
+Listen for keyboard input to send commands.
+
+Usage:
+
+```python
+from tdw.keyboard_controller import KeyboardController
+from tdw.tdw_utils import TDWUtils
+
+def stop():
+    done = True
+
+done = False
+c = KeyboardController()
+c.start()
+
+# Quit.
+c.listen(key="esc", commands=None, function=stop)
+
+# Equivalent to c.start()
+c.listen(key="r", commands={"$type": "load_scene", "scene_name": "ProcGenScene"}, function=None)
+
+while not done:
+    # Receive data. Load the scene when r is pressed. Quit when Esc is pressed.
+    c.communicate([])
+# Stop the build.
+c.communicate({"$type": "terminate"})
+```
+
+***
+
+#### `stop()`
+
+def __init__(self, port: int = 1071, check_version: bool = True, launch_build: bool = True):
+
+***
+
+#### `__init__(self, port: int = 1071, check_version: bool = True, launch_build: bool = True)`
+
+Create the network socket and bind the socket to the port.
+
+| Parameter | Description |
+| --- | --- |
+| port | The port number. |
+| check_version | If true, the controller will check the version of the build and print the result. |
+| launch_build | If True, automatically launch the build. If one doesn't exist, download and extract the correct version. Set this to False to use your own build, or (if you are a backend developer) to use Unity Editor. |
+
+***
+
+#### `communicate(self, commands: Union[dict, List[dict]]) -> list`
+
+Listen for when a key is pressed and send commands.
+
+| Parameter | Description |
+| --- | --- |
+| key | The keyboard key. |
+| commands | Commands to be sent when the key is pressed. |
+| function | A function to be invoked when the key is pressed. |
+
+***
+
+#### `listen(self, key: str, commands: Union[dict, List[dict]] = None, function=None) -> None`
+
+Listen for when a key is pressed and send commands.
+
+| Parameter | Description |
+| --- | --- |
+| key | The keyboard key. |
+| commands | Commands to be sent when the key is pressed. |
+| function | A function to be invoked when the key is pressed. |
+
+***
+
diff --git a/Documentation/python/py_impact.md b/Documentation/python/py_impact.md
index 7d1b55d1b..217bfd2ac 100644
--- a/Documentation/python/py_impact.md
+++ b/Documentation/python/py_impact.md
@@ -327,20 +327,20 @@ c.start()
 
 # Request the required output data (do this at the start of the simulation, not per frame).
 resp = c.communicate([{"$type": "send_collisions",
-"enter": True,
-"exit": False,
-"stay": True,
-"collision_types": ["obj", "env"]},
-{"$type": "send_rigidbodies",
-"frequency": "always"}])
+                       "enter": True,
+                       "exit": False,
+                       "stay": True,
+                       "collision_types": ["obj", "env"]},
+                      {"$type": "send_rigidbodies",
+                       "frequency": "always"}])
 
 # Parse the output data and get collision type data.
 ctof = CollisionTypesOnFrame(object_id, resp)
 
 # Read the dictionaries of collidee IDs and collision types.
 for collidee_id in ctof.collisions:
-collision_type = ctof.collisions[collidee_id]
-print(collidee_id, collision_type)
+    collision_type = ctof.collisions[collidee_id]
+    print(collidee_id, collision_type)
 
 # Check the environment collision.
 print(ctof.env_collision_type)
diff --git a/Documentation/python/tdw.md b/Documentation/python/tdw.md
index e0105ad1f..c7399cd4b 100644
--- a/Documentation/python/tdw.md
+++ b/Documentation/python/tdw.md
@@ -12,15 +12,16 @@ pip3 install tdw
 
 ### Frontend
 
-|                                                              | Description                                                 |
-| ------------------------------------------------------------ | ----------------------------------------------------------- |
-| [Controller](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/controller.md) | Base class for all controllers.                             |
-| [TDWUtils](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/tdw_utils.md) | Utility class.                                              |
-| [AssetBundleCreator](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/asset_bundle_creator.md) | Covert 3D models into TDW-compatible asset bundles.         |
-| [PyImpact](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/py_impact.md) | Generate impact sounds at runtime.                          |
-| [DebugController](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/debug_controller.md) | Child class of `Controller` that has useful debug features. |
-| [Librarian](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/librarian/librarian.md) | "Librarians" hold asset bundle metadata records.            |
-| [FluidTypes](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/fluid_types.md) | Access different NVIDIA Flex fluid types.                   |
+|                                                              | Description                                                  |
+| ------------------------------------------------------------ | ------------------------------------------------------------ |
+| [Controller](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/controller.md) | Base class for all controllers.                              |
+| [TDWUtils](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/tdw_utils.md) | Utility class.                                               |
+| [AssetBundleCreator](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/asset_bundle_creator.md) | Covert 3D models into TDW-compatible asset bundles.          |
+| [PyImpact](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/py_impact.md) | Generate impact sounds at runtime.                           |
+| [DebugController](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/debug_controller.md) | Child class of `Controller` that has useful debug features.  |
+| [KeyboardController](keyboard_controller.md)                 | Child class of `Controller` that can listen for keyboard input. |
+| [Librarian](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/librarian/librarian.md) | "Librarians" hold asset bundle metadata records.             |
+| [FluidTypes](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/fluid_types.md) | Access different NVIDIA Flex fluid types.                    |
 
 ### Backend
 
diff --git a/Python/example_controllers/keyboard.py b/Python/example_controllers/keyboard.py
deleted file mode 100644
index b4f6cdfbb..000000000
--- a/Python/example_controllers/keyboard.py
+++ /dev/null
@@ -1,85 +0,0 @@
-from tdw.controller import Controller
-from tdw.tdw_utils import TDWUtils
-from platform import system
-
-if system() == "Windows":
-    from msvcrt import getch
-else:
-    from getch import getch
-
-
-"""
-Use WASD or arrow keys to move an avatar.
-"""
-
-
-class KeyboardControls(Controller):
-    def run(self, force=80):
-        """
-        :param force: The force magnitude used to move the avatar.
-        """
-
-        print("W, up-arrow = Move forward")
-        print("S, down-arrow = Move backward")
-        print("A, left-arrow = Turn counterclockwise")
-        print("D, right-arrow = Turn clockwise")
-        print("Esc = Quit")
-
-        self.start()
-        self.communicate(TDWUtils.create_empty_room(12, 12))
-        self.communicate(TDWUtils.create_avatar(avatar_type="A_Img_Caps"))
-
-        # Set high drag values so it doesn't feel like the avatar is sliding on ice.
-        self.communicate({"$type": "set_avatar_drag",
-                          "drag": 10,
-                          "angular_drag": 20})
-
-        # Change the floor material so it's easier to visualize the avatar's movement.
-        self.communicate([self.get_add_material("parquet_alternating_orange", library="materials_high.json"),
-                          {"$type": "set_proc_gen_floor_material",
-                           "name": "parquet_alternating_orange"},
-                          {"$type": "set_proc_gen_floor_texture_scale",
-                           "scale": {"x": 8, "y": 8}}])
-
-        done = False
-        while not done:
-            ch = getch()
-            ch_int = ord(ch)
-            forward = 0
-            torque = 0
-            # Move forward with w or up-arrow.
-            if ch == b'w' or ch_int == 72:
-                forward = force
-            # Move backward with s or down-arrow.
-            elif ch == b's' or ch_int == 80:
-                forward = -force
-            # Rotate counterclockwise with d or right-arrow.
-            elif ch == b'd' or ch_int == 77:
-                torque = force
-            # Rotate clockwise with a or left-arrow.
-            elif ch == b'a' or ch_int == 75:
-                torque = -force
-            # Quit with esc.
-            elif ch_int == 27:
-                done = True
-                continue
-
-            commands = []
-            # If there was any directional input, apply a directional force.
-            if abs(forward) > 0:
-                commands.append({"$type": "move_avatar_forward_by",
-                                 "magnitude": forward})
-            # If there was any rotational input, apply a torque.
-            if abs(torque) > 0:
-                commands.append({"$type": "turn_avatar_by",
-                                 "torque": torque})
-
-            # If there was no input, do nothing and advance the simulation.
-            # (This isn't necessary in this example, but you'll want this if anything else is moving in the scene).
-            if len(commands) > 0:
-                commands.append({"$type": "do_nothing"})
-
-            self.communicate(commands)
-
-
-KeyboardControls().run()
diff --git a/Python/example_controllers/keyboard_controls.py b/Python/example_controllers/keyboard_controls.py
new file mode 100644
index 000000000..1fa0f1ae2
--- /dev/null
+++ b/Python/example_controllers/keyboard_controls.py
@@ -0,0 +1,86 @@
+from tdw.keyboard_controller import KeyboardController
+from tdw.tdw_utils import TDWUtils
+
+
+"""
+Use WASD or arrow keys to move an avatar.
+"""
+
+
+class KeyboardControls(KeyboardController):
+    def __init__(self, port: int = 1071):
+        super().__init__(port=port)
+        self.done = False
+
+    def run(self, force=80, torque=100):
+        """
+        :param force: The force magnitude used to move the avatar.
+        :param torque: The torque magnitude to turn the avatar by.
+        """
+
+        print("W, up-arrow = Move forward")
+        print("S, down-arrow = Move backward")
+        print("A, left-arrow = Turn counterclockwise")
+        print("D, right-arrow = Turn clockwise")
+        print("Esc = Quit")
+
+        # Listen for keyboard input for movement.
+        self.listen("w", commands={"$type": "move_avatar_forward_by",
+                                   "magnitude": force,
+                                   "avatar_id": "a"})
+        self.listen("up", commands={"$type": "move_avatar_forward_by",
+                                    "magnitude": force,
+                                    "avatar_id": "a"})
+        self.listen("s", commands={"$type": "move_avatar_forward_by",
+                                   "magnitude": -force,
+                                   "avatar_id": "a"})
+        self.listen("down", commands={"$type": "move_avatar_forward_by",
+                                      "magnitude": -force,
+                                      "avatar_id": "a"})
+        self.listen("d", commands={"$type": "turn_avatar_by",
+                                   "torque": torque,
+                                   "avatar_id": "a"})
+        self.listen("right", commands={"$type": "turn_avatar_by",
+                                       "torque": torque,
+                                       "avatar_id": "a"})
+        self.listen("a", commands={"$type": "turn_avatar_by",
+                                   "torque": -torque,
+                                   "avatar_id": "a"})
+        self.listen("left", commands={"$type": "turn_avatar_by",
+                                      "torque": -torque,
+                                      "avatar_id": "a"})
+        # Listen for keyboard input to quit.
+        self.listen("esc", function=self.stop)
+
+        self.start()
+        # Create the room.
+        commands = [TDWUtils.create_empty_room(12, 12)]
+        # Create the avatar.
+        commands.extend(TDWUtils.create_avatar(avatar_type="A_Img_Caps", avatar_id="a"))
+        # 1. Set high drag values so it doesn't feel like the avatar is sliding on ice.
+        # 2. Set the room's floor material.
+        commands.extend([{"$type": "set_avatar_drag",
+                          "drag": 10,
+                          "angular_drag": 20,
+                          "avatar_id": "a"},
+                         self.get_add_material("parquet_alternating_orange", library="materials_high.json"),
+                         {"$type": "set_proc_gen_floor_material",
+                          "name": "parquet_alternating_orange"},
+                         {"$type": "set_proc_gen_floor_texture_scale",
+                          "scale": {"x": 8, "y": 8}}])
+        self.communicate(commands)
+        while not self.done:
+            # Listen for keyboard input to add other commands.
+            self.communicate([])
+        self.communicate({"$type": "terminate"})
+
+    def stop(self):
+        """
+        Stop the controller and the build.
+        """
+
+        self.done = True
+
+
+if __name__ == "__main__":
+    KeyboardControls().run()
diff --git a/Python/setup.py b/Python/setup.py
index 14426a80d..33cfebf85 100644
--- a/Python/setup.py
+++ b/Python/setup.py
@@ -31,5 +31,5 @@
     include_package_data=True,
     keywords='unity simulation ml machine-learning',
     install_requires=['pyzmq', 'numpy', 'scipy', 'pillow', 'tqdm', 'psutil', 'boto3', 'botocore', 'requests',
-                      "pyinstaller"],
+                      'pyinstaller', 'keyboard'],
 )
diff --git a/Python/tdw/keyboard_controller.py b/Python/tdw/keyboard_controller.py
new file mode 100644
index 000000000..a73bb9f78
--- /dev/null
+++ b/Python/tdw/keyboard_controller.py
@@ -0,0 +1,84 @@
+from typing import List, Union
+import keyboard
+from tdw.controller import Controller
+
+
+class KeyboardController(Controller):
+    """
+    Listen for keyboard input to send commands.
+
+    Usage:
+
+    ```python
+    from tdw.keyboard_controller import KeyboardController
+    from tdw.tdw_utils import TDWUtils
+
+    def stop():
+        done = True
+
+    done = False
+    c = KeyboardController()
+    c.start()
+
+    # Quit.
+    c.listen(key="esc", commands=None, function=stop)
+
+    # Equivalent to c.start()
+    c.listen(key="r", commands={"$type": "load_scene", "scene_name": "ProcGenScene"}, function=None)
+
+    while not done:
+        # Receive data. Load the scene when r is pressed. Quit when Esc is pressed.
+        c.communicate([])
+    # Stop the build.
+    c.communicate({"$type": "terminate"})
+    ```
+    """
+
+    def __init__(self, port: int = 1071, check_version: bool = True, launch_build: bool = True):
+        """
+        Create the network socket and bind the socket to the port.
+
+        :param port: The port number.
+        :param check_version: If true, the controller will check the version of the build and print the result.
+        :param launch_build: If True, automatically launch the build. If one doesn't exist, download and extract the correct version. Set this to False to use your own build, or (if you are a backend developer) to use Unity Editor.
+        """
+
+        # Commands that should be added due to key presses on this frame.
+        self.on_key_commands: List[dict] = []
+
+        super().__init__(port=port, check_version=check_version, launch_build=launch_build)
+
+    def communicate(self, commands: Union[dict, List[dict]]) -> list:
+        if isinstance(commands, dict):
+            commands = [commands]
+        # Add commands from key presses.
+        commands.extend(self.on_key_commands[:])
+        # Clear the on-key commands.
+        self.on_key_commands.clear()
+        return super().communicate(commands)
+
+    def listen(self, key: str, commands: Union[dict, List[dict]] = None, function=None) -> None:
+        """
+        Listen for when a key is pressed and send commands.
+
+        :param key: The keyboard key.
+        :param commands: Commands to be sent when the key is pressed.
+        :param function: A function to be invoked when the key is pressed.
+        """
+
+        if commands is not None:
+            keyboard.on_press_key(key, lambda e: self._set_frame_commands(commands))
+        if function is not None:
+            keyboard.on_press_key(key, lambda e: function())
+
+    def _set_frame_commands(self, commands: Union[dict, List[dict]]) -> None:
+        """
+        Set the next frame's commands.
+
+        :param commands: The commands to send on this frame.
+        """
+
+        if isinstance(commands, dict):
+            commands = [commands]
+        self.on_key_commands = commands
+
diff --git a/README.md b/README.md
index 1f8211537..35e38746d 100644
--- a/README.md
+++ b/README.md
@@ -29,16 +29,17 @@
 
 ##### Frontend
 
-| Document                                                     | Description                                                 |
-| ------------------------------------------------------------ | ----------------------------------------------------------- |
-| [`tdw` module](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/tdw.md) | Overview of the Python `tdw` module.                        |
-| [Controller](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/controller.md) | Base class for all controllers.                             |
-| [TDWUtils](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/tdw_utils.md) | Utility class.                                              |
-| [AssetBundleCreator](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/asset_bundle_creator.md) | Covert 3D models into TDW-compatible asset bundles.         |
-| [PyImpact](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/py_impact.md) | Generate impact sounds at runtime.                          |
-| [DebugController](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/debug_controller.md) | Child class of `Controller` that has useful debug features. |
-| [Librarian](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/librarian/librarian.md) | "Librarians" hold asset bundle metadata records.            |
-| [FluidTypes](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/fluid_types.md) | Access different NVIDIA Flex fluid types.                   |
+| Document                                                     | Description                                                  |
+| ------------------------------------------------------------ | ------------------------------------------------------------ |
+| [`tdw` module](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/tdw.md) | Overview of the Python `tdw` module.                         |
+| [Controller](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/controller.md) | Base class for all controllers.                              |
+| [TDWUtils](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/tdw_utils.md) | Utility class.                                               |
+| [AssetBundleCreator](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/asset_bundle_creator.md) | Covert 3D models into TDW-compatible asset bundles.          |
+| [PyImpact](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/py_impact.md) | Generate impact sounds at runtime.                           |
+| [DebugController](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/debug_controller.md) | Child class of `Controller` that has useful debug features.  |
+| [KeyboardController](Documentation/python/keyboard_controller.md) | Child class of `Controller` that can listen for keyboard input. |
+| [Librarian](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/librarian/librarian.md) | "Librarians" hold asset bundle metadata records.             |
+| [FluidTypes](https://github.com/threedworld-mit/tdw/blob/master/Documentation/python/fluid_types.md) | Access different NVIDIA Flex fluid types.                    |
 
 ##### Backend