One of my housemates returned to school last August with a canine companion named Winston. He's a miniature Schnauzer, and is now about 10 months old. Even at such a tender age, he has already compiled a long list of "dietary indiscretions," also known as "stuff he shouldn't have eaten." This list is just to get us going. I fully expect this to become a regularly-appearing topic.
Chocolate (including Hershey kisses, a raspberry-filled Gertrude Hawk dark chocolate bar from the box I'm supposed to be selling for a fundraiser, mini Reese's cups, M&Ms, and peanut M&Ms)
An entire, unopened pack of chewing gum
Used tissues, straight from the trashcan
An entire bag of kitty treats
Ibuprofen (more than once)
A tube of hydrocortisone anti-itch cream
PPA, a drug used to treat canine urinary incontinence
So much dry cat food in one sitting that he vomited intact cat food kibbles overnight, and was pooping intact cat food kibbles the next morning. Basically his entire GI tract was full of cat food.
The tasty treats the cats hide in their litter boxes...yes...you know what I mean.
So, that's all I can think of off the top of my head.