Let see here. We got Spongebob, Patrick, Squidward, Sandy Ceeks, Zim, Gir, CatDog, Tommy, Chuckie, Angelica, Reptar, The 4 Ninja Turtles (Leonardo, Raphael, Donatello, & Michelangelo), As well as their Archenemy (Shreddar), Jojo Siwa, Ren & Stimpy, Arnold, Gerald, Helga, Danny Phantom, Rocko, Heffer, Aang, Korra, and of course, Lincoln, Lucy, and Clyde.
So all in all, we have a bit more variety of characters from different Nick Shows in this sequel compare to the first Kart Racers from 2018, where it only have 12 characters from only 4 Nick Shows. But there are still missing some characters from other shows like The Fairly Oddparents, Jimmy Neutron, My Life As A Teenage Robot, The Casagrandes, etc.
Also, there's no Plankton, no Vlad Plasma, no Zuko, no Mr. Krabs, no Sam Manson, no Ronnie Anne, no Master Splinter, no the rest of the Loud Sisters, no other characters from these series that are important to Nick history, as well as to these Nick Shows. Even though the game said that there are companion characters, I sure wish that some of them are actual racers.