I think this might happen anyway since this wiki has a page on his universe but none the less I'd still love to see Rex Salazar to make an appearance in this series
Defiantly Generator Rex and Tetrax Shard!
Generator Rex and Dark Danny as well as some of the canon transformations we never saw in any of the shows or movies but are still canon (Ex. Shellhead, Rocks, Squidstrictor).
Here's a random answer that I don't think anyone has thought of before, The Spectacular Spider-Man.
If I had to choose one, Walker for DP, and for B10 I'd say Reiny (Think I'm spelling it right).
Also, Marvel's Thor appearance would be cool.
I say any Ben 10 alien but with overkill on it
I want to say that how about we can see more ben's from alternate universes and one of the strongest ben who watch is way much stronger and powerful than any other ben universe or any other universe
I wanna see Nigel Uno make another, bigger appearance besides his cameo in Chapter 9, and I'm sure Alien-X is coming up soon already. Also, I think it would be totally awesome if the Highbreed Reinrassig III, aka "Reinny" from the episode Alone Together and later the season 2 finale of Alien Force, made a surprise appearance!
But If it were possible to bring in ANYONE, I want to see Wally West Flash from the Young Justice cartoon, in a hypothetical story where he accelerated into the Speed-Force, achieved enlightenment, became a super-insanely OP Speedster-God like he is in the comics, and is now travelling the Omniverse at ridiculously infinite speeds on his way back home to be with Artemis, but keeps getting slowed down helping save people in danger across the Omniverse. In terms of design, he'd look like Silver-Surfer now, but instead of silver, he's bright scarlet-red with golden eyes and outline, and golden starry-sparkles decorating his glowy-red body, and a matching hoverboard. He'll basically be the most OP Speedster EVER, with Speed and Power on an OMNIVERSAL scale, and I shall call him... The FOREVER-FLASH!!!
So, what do ya think? Cool idea?
Wally West is my Favorite Superhero EVER, and I'd LOVE to see the Ink Tank do him some epic 5YL justice! Plus it would tie into Young Justice, another Cartoon Network gem that was screwed over for a time! It would be AWESOME! XD
Either another, bigger appearance for Nigel Uno, or Wally West from the Young Justice series, after returning from his supposed death, and now INSANELY OP thanks to his newfound affinity with the Speed-Force.