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.
Blind Chess using Taiwan rules
A promising chess program
javascript chess games viewer for websites, blogs and live broadcasts
Chess Cheats for Personal use
Logical game
Chess pairing program for run through and round robin tournaments
The forever free, ad-free and open source chess server
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
Next generation web chess club
A simple chess board for Android (>= API 3)