Pachi is an open source go playing program (engine) or go-bot. It is being actively developed.
It reached 4d on kgs server (account Pachi2 cluster version)
GOWrite 2 is a full-featured SGF viewer, editor and publishing tool for game of Go. Go is known in Japan as go(囲碁), in China as weichi(围棋), and in Korean as baduk(바둑).
GOWrite 2 special strengths are in publication creation. See the Fact sheet for list of features.
GOWrite 2 is freeware.
qGo (Linux)1.5.4-r3 sabaki-source0.31.4 
Fuego is a collection of C++ libraries and includes a playing engine. It is written by Markus Enzenberger?, Martin Mueller and Broderick Arneson of the ![[ext]](https://senseis.xmp.net/images/extlink.gif)
Computer Go group at the University of Alberta, Canada. Fuego uses Monte Carlo Tree Search for playing the game of Go.
gowrite2 (Mac)2.3.46 
GOWrite 2 is a full-featured SGF viewer, editor and publishing tool for game of Go. Go is known in Japan as go(囲碁), in China as weichi(围棋), and in Korean as baduk(바둑).
GOWrite 2 special strengths are in publication creation. See the Fact sheet for list of features.
GOWrite 2 is freeware.
IGoEnchi is an IGS client and SGF editor for Windows Mobile based devices
MoGo: a Grid5000-based software for the Game of Go
