Sunfish: a Python Chess Engine in 111 lines of code
A promising chess program
Chess application whichs allows working with chess PDF books and PGNs.
Chess Database and PGN viewer
a UCI chess engine
Chess program
Julia chess programming library
SJCE - free portable cross-platform graphical chess game, 100% Java.
Java Chess Engine
icsdrone is an interface between a chess server and a chess engine
Yet Another Chess ENgine