UCI chess engine
Prebuilt UCI- and XBoard-compatible chess engines.
Portable UCI- and XBoard-compatible chess engines.
Scripts and tools for building and testing chess engines.
A promising chess program
Blind Chess using Taiwan rules
Chess Cheats for Personal use
Logical game
RelaxChess, chess game that makes no search futher needed for a wow
A JavaScript game library to quickly develop board games for the web
0xBench derivative
A simple chess board for Android (>= API 3)