Alex, Jack, Julie and Katie Power are four preteens granted superpowers by an alien who resembled a horse. The team would fit well in a Big Hero 6-type animated movie.
This mutant and occasional X-Man with the ability to emit light beams is actually pop singer Alison Blaire who moonlights as a hero. Sort of like a superpowered Hannah Montana, really.
The Marvel equivalent of DC’s Teen Titans, the Young Avengers are a team of teen versions of familiar heroes e.g. Iron Lad, Hulkling, Miss America, Speed and Wiccan and Kid Loki.
Sometimes called a female Punisher, Silver Sable often comes up against Spidey as a vigilante who isn’t afraid to kill to stop the bad guys. She’s not superpowered, just highly trained.
Marc Spector is imbued with power (which intensifies when the moon is full) by Egyptian Gods. A fan favourite anti-hero who suffers from multiple personality disorder.