I wanted to print an Expando (by Zando2k) for my daughter to play with. But I didn't want to just make it blank, or to put some "3D printing" text logo. So I added an embossed silhouette of Anna from Frozen that I borrowed from a coaster model (by Angelkoh).
My daughter likes it!
The author marked this model as their own original creation. Imported from Thingiverse.