I noticed for one of the largest communities, there was no icon! It looks strange in the Communities view. Anyways, I mocked these up trying to use the Lemmy logo. If you like any of them but it’s not quite right, I can adjust it - or if you have a new idea, I’m down to try that too!
I like the 1st one. I think I would like it even more if you filled in the nose with the black making it the dot in the question mark instead of a square dot.