XBoard - XBoard, also known as WinBoard on Microsoft operating systems, is a free graphical user interface...
SkillGamesBoard - Play free online games against thousands of players, work out your own techniques, and improve your logical thinking skills in turn-based multiplayer board games on SkillGamesBoard!
ChessDB - ChessDB - a free Chess database for Mac OS X, Windows, Linux, and UNIX - like ChessBase, but better
Gomoku - Online Game Hall - This is the most powerful gomoku game on Mac App Store. For the game rule:
Lichess - The complete chess experience, play and compete in tournaments with friends others around the world.
4 in a Row - 4 in a Row, the classic game that's easy to understand, but hard to master.