It's impossible to overstate how successful Teenage Mutant Ninja Turtles was a franchise throughout the 80s and into the early 90s. Of course, this meant that other companies wanted in on the same kind of money, and the results we got were shows like this that definitely copied it, but were pretty awesome in their own right. Shows like;
Biker Mice From Mars
They were alien mice that rode motorcycles, listened to heavy metal, and fought aliens with lasers, chains, and attitude. What else could you possibly want from a cartoon?
After the sons of a disgraced scientist have their DNA spliced with that of various types of sharks by their father's evil partner, they become the Street Sharks and duke it out with other genetically mutated humans. It's almost verbatim the plot of TMNT but features heroes that can literally chew their way through anything!
Transformed into humanoid fighters by an alien force, a team of various dinosaurs has to battle the alien's combined forces with a collection of laser weapons and their own jaws. Pretty stupid, but pretty awesome.
Based on the NES video game developed by Rare, the Battletoads cartoon was a half-hour special by the same team behind Extreme Dinosaurs. It followed Rash, Zitz and Pimple as they fought the Dark Queen to save their Princess Angelica, but it didn't captivate audiences and never moved past the one special.
Those were probably the best copycats, and from here it only gets weirder...
Remember those Troll dolls that were really big? The ones where they had gems embedded in them and they never wore pants? Someone decided that those needed to be EXTREME and HARDCORE, MAN! The result was this weird, kinda hilarious hybrid.
Disney took a movie trilogy about a pee-wee hockey team and made it into a sci-fi epic about alien ducks who play hockey and defend the Earth against an alien overlord voiced by Tim Curry. Stupid as hell, but also pretty awesome.
Samurai Pizza Cats
One of the few bits of Japanese anime to get brought over before Sailor Moon and Dragon Ball Z became huge, this feature 3 cybernetic cats who delivered pizza and fought ninjas. Nothing beat its catchy-ass theme song.
Wild West C.O.W.-Boys of Moo Mesa
They were cows who were also cowboys. And the show was filled with cow puns. I really don't know what else to tell you.
Bucky O'Hare and the Toad Wars
A group of space commando rabbits fought an army of toads, and the results were a catchy theme song and some pretty fun episodes. Even spawned a pretty great NES game.
One of the last real attempts at a TMNT-esque action cartoon in the 90s, Mummies Alive was one of the good ones. A young boy finds out he's the reincarnation of an ancient Egyptian prince, and that he's been targeted by an evil sorcerer for thousands of years. Thankfully, he has a team of warriors who've been raised from the dead to defend him!