Tatoruzu the other ones besides Pete that were created for the 2012 series were
Tiger claw, Fishface, snakeweed, dream beavers, sal commander, kraang prime, kraang sub prime, monkey brains, sir Malachi, chompy, jack kurtzman, ice cream kitty, Dr Cluckingsworth, Justin, Shinigami, Mira, Squirrelanoids, Ho Chan, Fungus Humungous, Spyroach, the creep, speed demon, chimera, Don Vizioso, Kavaxas and Verminator Rex.
i don't think Spider Bytez and Newtralizer count since there was a mutant spider monster with the same name from the 2003 series and newtralizer was based on a scrapped character from the original TMNT toy-line