Zsh is a project mainly written in ..., it's free.
zsh snippets
This contains some zsh functions I find useful. To use them, either:
1) Create a directory ~/.zsh/functions and put the files you need in there 2) Put something like this into your zshrc
if [ -e $HOME/.zsh/functions ]; then autoload $HOME/.zsh/functions/*(:t) fi
or copy the content of the files to your zshrc.