I didn’t screenshot any of them, but I once saw a dandelion growing on the same square as a tree, and a datura plant growing in a square of the lava that indicates underground rifts. The apocalypse certainly made some sturdy plants.
Just like redxlaser, I’ve also seen some fierce raccoons. One of them took down a full health giant wolf spider, without taking a single scratch itself.
Also, like TheMurderUnicorn, I once found a trenchcoat and a bag of crack on a Zombie Child.
Once, some time ago, I noticed a disproportionately high number of X-Acto Knives dropping from Crawling Zombies. I remember thinking, “Well, now I know how they got that way.”
Aside from those, nothing terribly interesting, though.