Oh My Zsh comes bundled with plugins, which allow you to take advantage of functionality of many sorts to your shell just by enabling them. They are each documented in the README file in their respective plugins/ folder.
Enable a plugin by adding its name to the plugins array in your .zshrc file (found in the $HOME directory). For example, this enables the rails, git and ruby plugins, in that order:
I use the elixir and git plugins a lot. I love the gwip and gunwip aliases. My zsh theme works with them so I can see when I switch to a branch that has a WIP commit. I find it much better than git stash.
I used to use omz as well, though eventually it felt as if most add-ons just were some curated and opinionated aliases I didn’t use anyway, so I removed it, and managed my aliases manually from then on.