Stylized animation is my favorite type of animation. Getting started is always difficult, but YouTube has an unlimited number of videos to help beginners get started. Click the button below to be taken to a YouTube playlist that focuses on Stylized animations and grease pencil.
Blender has plenty of free, and paid plug ins. Since it is also open source, anyone in the community can make their own to sell, or to list for free! Some good ones are: -Ucupaint -Rigify -Auto Mirror -Bool Tool -Extra Mesh Objects