I noticed I needed to add one Pipsqueak to fill in that space in the top row. So I just placed one just for good measure. Anyway, this is the twelve set. Some of them are artists I like, some are underrated, and some are more noticable.

ROW 1: Sylvester & Tweety, Engie Ear, Slimer, Chibi Maruko, Stan Marsh, Postal Dude, Untitled Goose, Rosalina & Luma, Camhead, Mr. Poofers, Dr. Weird, Courage

ROW 2: Inspector Gadget, Knuckles, Calcetín con Rombos Man, Claptrap, Jimmy Basillisk, Annalynn, The Maxx, Fred

ROW 3: Man on the Internet, Stanley Ipkiss (The Mask), Marvin the Paranoid Android, Aran, Wabuu, Cartoon Cat, Question Hound, Rebecca Doodles, Zarenta, Bertin