DejaGnu - DejaGnu is a framework for testing other programs.
SmallDevTools - Handy developer tools with a delightful interface
Expect - Expect is a tool for automating interactive applications such as telnet, ftp, passwd, fsck, rlogin...
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Check - Check is a unit testing framework for C, which runs on environments such as GNU/Linux, GNU/Hurd, BSD, and Mac OSX.
Profitable developer tools database - A database of 103+ hand-curated profitable developer tools