Modern comic fans may know Captain America like the back of their hand, but it's another Marvel super-soldier who takes the cake. The being known as Sentry is absolutely one of the most powerful characters in the Marvel Universe, which means fans should all know him, even if he hasn't appeared on film. Said to hold the power of "a million exploding suns," strong enough to fight the Hulk to a standstill, and blessed with telepathy, immortality, and even the ability to resurrect the dead, there isn't much Sentry can't do. In fact, he may be one of the truly invincible characters in Marvel's entire universe.
Jean Grey (Marvel)
There's no shortage of psychics in Marvel's catalogue, so being the best of them is saying something. That honor *probably* goes to Jean Grey, the fifth member of the original X-Men. The live-action movies only scratched the surface of Jean's powers, since her decades in print have shown her do just about anything a mind can achieve: mind-reading, mind control, telekinetic barriers, force fields, you name it. And that's even before she unlocks full access to the cosmic Phoenix Force - it may make her a bit more villainous, but the power it grants over the universe as a whole is testament to Jean's dedication and focus.
Shazam (DC Comics)
We know what you'e thinking: it's Superman who has to be DC's strongest hero, right? Not necessarily. Superman was first, but with updates and imitators came some serious upgrades. Take Shazam, formerly known as Captain Marvel. All the powers, all the strength, all the speed and invulnerability of Superman, but drawn straight from the magical gods of the ancient world. That basically means that the champion of the old gods can go toe-to-toe with Superman, and actually hurt him (since the Man of Steel, like most alien villains, is vulnerable to magic). Not to mention being fast enough to challenge The Flash, and not needing to eat or sleep while in his superhero form. Something almost no other heroes can claim.
We couldn't leave the Man of Steel out in the cold, since he's easily DC's biggest icon, and a representative of comics as a whole. By now, nobody needs to be told how his alien skin renders him bulletproof to most attacks - except magical - or how he flies from one emergency to the next. But no matter how busy or convoluted his stories have been over the years, it's hard to argue the charm of a Greek demigod like Superman in our midst.
The Flash (DC)
It might sound like running really fast would get old quickly, but Barry Allen's comic book powers are on another level. When you have the superhuman speed to casually stroll past almost-frozen people beside you, it's hard to think of a superpower that couldn't just be faked using the same strategy. But that was before Barry Allen realized he had the speed to travel to distant worlds, or even back in time. And for all the muscles and alien physiology to choose from, a hero who can rewrite time in the blink of an eye is as powerful as they come.
Doctor Strange (Marvel)
Imagine if Harry Potter was a grown man, and well-trained in martial arts? Now picture it a whole lot cooler, and you've got a rough idea of why Doctor Stephen Strange is basically just that. Having learned the ways of mystic magic, martial arts, and claimed the title of 'Sorcerer Supreme' for himself, it's true that Strange relies on amulets and symbols for power, not his powers or mutation. But he's been referred to as the most powerful human on Earth - so magic wands, necklaces, or orbs aside, Strange is the heavyweight hitter of Marvels' supernatural side. Here's hoping it makes it to the big screen soon.