Came across it from Mental Floss, make sure you check out the albums as there's even a Space one! Shoutouts to insomniasexx, tla, as I know you've been interested in digital archives being shared and I've started the #archives tag :)
Some of my favourites:
Phases of the moon which I think would make an awesome Hubski sticker!
Das Kanapee In Der Sachsischen-schweiz literally "The sofa in the Saxon - Switzerland"; at first I thought it was translated wrong but when I went back and looked I facepalmed. It's a nice image and has this real un-charted lands adventure feel to it.
The Magpie I like the style of these, nathank might too, but I picked this one as we see a huge number of magpies where we live and my wife has this tradition of saluting solitary ones and saying "Good morning Mr. Magpie, how's your missus?" -- so I picked it because it made me think of her.