Well, I just got some cool icon ideas:
Abstract images with a style similar to the ones you can create here: https://msurguy.github.io/triangles/. Abstract backgrounds are cool, modern and also beautiful in my opinion.
Host an avatar challenge. Maybe host a challenge where Hopscotchers could code a profile picture. THT would pick one or multiple winners that will get their project as a profile picture available for subscribers and non-subscribers.
Those are two ideas I think would be cool to have in Hopscotch!