there are some concepts that i consider Quite Important, but most people don't know about them. so they'll be here. :)
plurality is, essentially, people who are Many, that is, there are more than one individual in their body. i have quite a number of friends who are a part of a system. a lot of people don't know about the existence of these, but they're very important and very much existing!
some more links which will explain things a lot better and also address questions and stuff:
ableism is easily the most common form of discrimination around, yet rarely anyone pays attention to it. words such as stupid and insane might sound fine to you, but really, they are Extremely Bad. i urge you to drop them from your vocabulary.