This is probably one of our favorite decoration ideas on this list, especially if you're doing the project with kids. If you are doing it with kids, then you can allow them to pick the materials for their bunnies or any decorations they might want to add after the stuffed bunnies are finished. If not, then feel free to choose from any material you like, and just stuff it using pom poms or cotton.
There are detailed instructions online, and it will take a little bit more time than some other ideas on this list, but if you do it right, then it'll last forever.