Shell-fu - Is a great site with a growing collection of command line goodies. What makes it interesting is that there are multiple combinations of commands which achieve different tasks. And users can submit and vote for their favourite commands.
Dot files - This site is a repository of collections of dot files. If you precede a file with a dot, it is considered as a hidden file in Linux. There are numerous hidden files in Linux. The standard ones being
.xinitrcand so on. But it doesn't limit to these files. Many applications create hidden files too.
Vimbits - This site lets you share you coolest trick, mapping, setting, or custom command for the Vim editor, Find new bits, and vote up the best ones.