pachi (Source)12.40 A fairly strong Go/Baduk/Weiqi playing program
Sabaki (Source)0.43.3 
A very nice graphical user interface for Windows, Mac and Linux
PANDA-gGo is a Go board, SGF editor, client for the Internet Go Server and an interface for playing with GNU Go. gGo is written in Java and available for Linux, OS X, OS/2 and Windows. gGo is distributed free of charge.
A fairly strong Go/Baduk/Weiqi playing program
Sabaki (Win64)0.43.3 
A very nice graphical user interface for Windows, Mac and Linux
Panda Egg is a graphic (non-ASCII) Go client for IGS. With it, you can play on and connect to IGS, as well as replay your games, if saved through the Egg in UGF format.
leela (Ubuntu)0.11.0 
Leela is a strong Go playing program combining advances in Go programming and further original research into a small, easy to use graphical interface.
Sabaki (Linux32)0.43.3 
A very nice graphical user interface for Windows, Mac and Linux
leela (Mac)0.11.0 
Leela is a strong Go playing program combining advances in Go programming and further original research into a small, easy to use graphical interface.
Sabaki (Linux64)0.43.3 
A very nice graphical user interface for Windows, Mac and Linux
