Some Plug-Ins have made it into the manual but generally it is hard to tell what is actually popular or useful since we don’t have any metrics (especially since they are hosted off site, like on the creators GitHub or their website) and everyone has their own opinion about what is useful.
Krita had a centralized place for resources once but:
So it is not out of question but with the core team fully involved with Krita already there are currently no people left to make this work and keep it maintained.
this topic already came up a few times. Everyone agrees this would be a cool thing to have but for now it doesn’t seem like it’s happening anytime soon.