The discussion of the TMNT/Batman crossover made me think of all of the intercompany and licensed crossovers we've seen through the years. Assuming that they're all cannon, that means that the following are all part of the DC "Universe." Superman <> Spiderman <> Transformers <> GI Joe Superman <> Spiderman <> Transformers <> My Little Pony JLA <> Avengers Teen Titans <> X-Men GLC <> Star Trek <> X-Men Batman <> TMNT <> Cerebus the Aardvark Batman <> Grendel (More than once!) Batman <> Predator Superman <> Aliens Batman <> Judge Dredd Batman <> Space Ghost DC <> Hanna Barbera properties (Scoobie Doo, etc.) Batgirl <> Ghost <> Dark Horse supers What else is out there?
Batman to TMNT to Daredevil DC Comics to Loony(Looney?) Tunes Possibly Batman to TMNT to Usagi Yojimbo(not sure whether that was comics or cartoon) Also, aren't Spawn and Heman connected to DC?
Justice league /power rangers cross over https://en.m.wikipedia.org/wiki/Justice_League/Mighty_Morphin_Power_Rangers
This wasn't a DC crossover, but IDW did a TMNT/Ghostbusters cross over and it was FANTASTIC. They did 2 of them. Excellent stuff. Lots of fun.
I looked it up. Spawn did crossover with Batman. He-man was connected to the Injustice Universe but I think I saw he also had a less recent crossover with the main DC universe and depending on how many degrees of separation, he also crossed over with Thundercats so you can add them to the list