I don't disagree with pinco here, but I think his response doesn't tell the whole story. I've released a few stand-alone plugins that function across multiple mods--unzip it to the UI's folder and it works.
It's up to the modder to design features that can stand alone or not; some are while others are not. As far as I've seen, most of the packaged UI mods have a lot of dependencies that prohibit this plug-and-play functionality.