The strongest among the open sources. Author: Fabien Letouzey.
An interesting Fruit clone. Author: Thomas Gaksch.
The father of all open sources. Author: 2 times worldchampion Bob Hyatt.
Starter kit for entrant chess programmers. Author: Tom Kerrigan.
Another starter kit for candidate chess programmers. Author: Bruce Moreland.
Very strong. Author: Tord Romstad.
Very strong. Author: Daniel Shawul.
Good. Author: Fabio Cavicchio.
Sophisticated chess engine. Author: John Dart.
The very first open source, the year is 1991. Authors: Stuart Cracraft and John Stanback.
Author: Dusan Dobes.
Author: Gian-Carlo Pascutto.