OK, my recollection was flawed. I did find another set with the same vibe around the time I found ubo earlier this year (buuf was a longtime fave) but I never combined it with the other two.
It's pretty incomplete compared with the others.
Name: umicons, based on the original icons by mattahan, the creator of buuf.
Screenshot from my Gnome 3 desktop in another distro:
The icons aren't very understandable. See the 1st 2 icons from the left in the dock below? The snake icon is Firefox (?!) and the blue blob next to it is Google Chrome.