Theoretically, only Nico Minoru is a D- (more like Z-)list character. Magik has had 4 comic runs and is Colossus' sister (+ she appeared in a recent movie), Robbie Reyes is Ghost Rider (not the most known one, but he's him), Captain Marvel had her own movie recently (a bad one, even by Marvel standards, but hey), Doctor Strange and Iron Man are two of the most popular Marvel characters. Blade is a bit of a weird case. He was very popular 20ish years ago but I have no idea what has been happening with him in the comics lately. Even then, he has 3 whole movies. However, you wouldn't know most of these people if you are a casual Marvel fan who has only seen the contemporary movies.
Maybe. I mean, eventually you get to people I knew, but originally, I was like: I guess comic super fans would be jizzing over this cast of literally whos? Half the time I was like: are these real characters or did they just make them up for the game? Oh there's also Blade, Spiderman, etc.