Sjeng - chess, audio and misc. software
Entertainment, Games, Board Games, Abstract, Battle Games - Sjeng. An attempt to create a bughouse and crazyhouse playing program that can attain a level comparable to the best human players.
https://sjeng.org/
Sunsetter Bughouse Engine
Entertainment, Games, Board Games, Abstract, Battle Games - Sunsetter Bughouse Engine. A program that plays chess and crazyhouse chess (single board bughouse) on internet chess servers, released under the GPL.
https://sunsetter.sourceforge.net/
NonVi Games home page
NonVi Games makes non-violent computer games including Double Chess, a program for PalmOS and Windows which plays both regular single-board and double-board (bughouse) chess.
http://www.nonvi.com
Bughouse.net!
Entertainment, Games, Board Games, Abstract, Battle Games - Bughouse.net. Rules, openings, strategy, rankings, and tournaments for a chess game in which two boards are used and four people can play.
http://www.bughouse.net/
Home page of The Chess Variant Pages
Rules, information, and links for games that are a variant of chess: three-dimensional chess games,multiplayer chess variants, historic chess variants, oriental variants, and many more. Look here also for some programs and a chess font.
https://www.chessvariants.com/
Witch's Chess
Hexenspiele, 666, Online shop, Hexen Bcher und Hexen Schach: Hexe, Hexenbesen, Hexenkessel, Fledermuse und Krten spielen auf einem Hexagon bzw. Hexeck Brettspiel
http://www.hexenspiel.de/
Swiss Perfect Home
Tournament management software for various sports and systems - Swiss, round-robin, knock-out.
http://www.swissperfect.com/