Sunfish is a simple, but strong chess engine, written in Python, mostly for teaching purposes. Without tables and its simple interface, it takes up just 111 lines of code! Yet it plays at ratings above 2000 at Lichess.

Because Sunfish is small and strives to be simple, the code provides a great platform for experimenting. People have used it for testing parallel search algorithms, experimenting with evaluation functions, and developing deep learning chess programs. Fork it today and see what you can do!

qtMUD is a Python package containing a MUD driver written by emsenn and released under the MIT License.

A personal file system indexing and search application. Part of the Gnome desktop. Indexes file contents, metadata, and location to better help you find things. Also allows you to do your own tagging of stuff it keeps track of. Uses D-BUS for IPC and SPARQL for search. Uses multiple ontologies for different kinds of files (including multimedia content).

MudPY is a MUD (multi-user dungeon) engine written in Python, which aims to be cross-platform, extensible, and easy to work with. Configuration is kept in text files. UTF-8 clean input and output.

Ren'Py is a game engine written in Python which makes it easy to develop certain kinds of games, namely, manga-style visual novels, turn-based battle games, space opera games, and point-and-click games similar to the old-school Lucasarts games (Maniac Mansion, et al) by incorporating Python development into the game authoring process. Incorporates a scripting engine to lay out the game, lets you use any or all of the Python sound and graphics libraries to implement the audiovisual content. Includes its own visual development environment (IDE) for implementing your game.