Nickelodeon All-Star Brawl's concept art has been shared and it shows characters that haven't made it into the game yet like Jimmy Neutron, Reggie from Rocket Power, Raphael and Casey Jones from TMNT, and more.
When Nickelodeon All-Star Brawl launched last year, one of the big questions on everyone's mind was what Nickelodeon characters were going to be coming to the game next and what ones weren't going to end up making it. Although we're still waiting to see who might be added after this first round of DLC characters, a piece of concept art has recently surfaced that gives us a bit of an idea about the original roster for the game, and who might even be yet to come.
The concept art, drawn by Christopher Near, shows a similar image as the final game's box art, so it looks like this was originally intended to be the roster. The most interesting thing about it is that it shows several characters who are now either DLC for the game, or haven't been announced at all.
Some of the characters here that aren't in the final game include Jimmy Neutron, Reggie Rocket, Raphael, Angelica from Rugrats, Kruum from Aah Real Monsters, Wanda from Fairly Odd Parents, and Casey Jones. In the final game, Raphael and Casey's spots as TMNT representative were replaced with Mikey and Leo, while Kruum was swapped for Oblina and Angelica for Reptar. Interestingly, although Jimmy Neutron didn't make it into the final game, his dad Hugh Neutron is currently the second DLC character announced and should be coming in the near future.
As pointed out by notjustcart00ns, the source who shared the concept art, this was before the game was officially revealed or in development and should just be considered a concept, "Please keep in mind that this art was created before development had even begun, characters being in here that aren't in the final game doesn't mean they were cut or off the table".