BuddyPress.org

As far as I know, there is not a widget that does that. It’s a good idea though!

You could create your own custom widget using the Featured Groups widget as a template. You would need to add CSS to create a grid pattern that positions the avatars the way you want. Here’s a post in which I describe how to make a very rudimentary grid structure using CSS.

If you do end up making this widget, consider sharing it with the community!