Zillions of Games -- Unlimited Board Games & Puzzles
Board games you can play with the computer, other people or over the Internet! Zillions of Games for Windows plays over 300 board games and puzzles. Change rules and add new games. Chess, Checkers, Reversi, Shogi, ...and more.
https://www.zillions-of-games.com/
Arasan Chess
Arasan is a chess program for Windows and Linux
https://www.arasanchess.org/
GNU WebChess
Entertainment, Games, Video Games, Recreation, Board Games - GNU WebChess. Chess servers hosting multiple games.
http://chess.delorie.com/
Dutch Internet Chess Server (DICS)
DICS a Free Internet Chess Server,part of DDS The Digital City A'dam! Play chess, watch chess, discuss chess,special,Blitz, tournaments,simuls,chess problems!
https://www.freechess.nl/
Play Online Chess at Caissa's Web
Caissa's Web is a free online chess server offering both live (real-time) and correspondence (turn-based) chess using a web browser (no software to download).
https://caissa.com/