What characters would you say i should buy if I can?

New player and I've been enjoying it so far. Ive bought a few bundles for characters I really like, like cosmic ghost rider, ghost rider, ghost rider Robbie, hela, zombie iron man, and the Deadpool bundle. Other than that, I was wondering what other characters should I buy if I get the chance? I could buy carnage and 2099 Spiderman rn, and they both look cool. But idk if they are good or revolve around a good team