Yay for mollusks! I actually have already made a project for this.
https://www.inaturalist.org/projects/freshwater-bivalves-of-the-world
I think North America should just be Unionida, Sphaeriida, Corbicula, Dreissena, and Mytilopsis.
You should also include gastropods! :)
https://www.inaturalist.org/projects/freshwater-gastropods-of-the-world