Sure, I didn't explicitly comment it but antigen can extend from “oh-my-zsh” (as you can see in the config example) and use all plugins already bundle from it.
# Load the oh-my-zsh's library.
antigen use oh-my-zsh
But, also adds the possibility to import any plugin from other resources. GitHub/Bitbucket/Gitlab and so on.
I like this, different from having to import manually to the “oh-my-zsh” plugins folder and maintain it by myself. (maybe a repo in your github account like omzsh-plugins solves the problem if you like this approach)
What do you think? I love to write new plugins and use with antigen, type zsh in my GitHub and you will see.