There are about 400 significant superbeings on Earth; distributed evenly about 1 for every 10 million population except that the U.S. has twice as many as it should have and China appears to have none so far as anybody knows. About 1/3rd of them protect human society and laws (let's call them "superheroes"), 2/3rd believe their own desires or plans override the rule of law (let's call them "supervillains", but not where they can hear us), and there don't appear to be any sitting on the sidelines. When a superbeing dies (rare), another one pops up eventually. There are estimates that perhaps 4000 people world wide have at least some paranormal ability but 90% of them aren't powerful to make any difference, and further estimates that perhaps 1 in 10 of the 400 are powerful enough to destroy a city. Speculation regarding whether the 1 in 10 step up in power applies to those 40 as well is strongly discouraged as being too unsettling to think about. There are a handful of people who dress up and play superbeing even though they don't have superpowers; it's pretty rough.
This is what the average US teenager somewhat interested in supers (as presumably our heroes are) would likely know, mostly from comic books and news reports. Someone from outside the US would, likely not know quite this much about US paranormals.
Apparently there were superbeings on both sides of WW II, ending abruptly in mid-1945 when The Golden Agency and their arch-enemies all died when the B-25 they were fighting in crashed into the Empire State Building. The Golden Agency included Liberator, Fox, Dreadnought and Torch, but their comics aren't as popular in the 80s and so you may not know much about them. They formed in the early 40's when they saved FDR, and seem to have spent most of the war foiling various insane plots by the brilliant Dr. Nazi, his unstoppable army of Aryandroids, and the Legion of Doom. The Legion and Dr. Nazi himself also died in the B-25 crash, and there was no super-being activity after that until the 60's.
The members of Team One saved President Reagan in 1983 and formed a team; the original members were Paladin, Key and Monolith. Laurentide joined in issue 4, Centurion in issue 25. Monolith turned out to be an alien princess and returned home to the stars in issue 50 (remember, this is how the comic book reports it). Key turned evil in issues 91-99 and Slipstream joined in issue 96; in 100 Key left the team for good. It's somewhere around issue 148 now. All the team members have their own comic books as well as the team book.
Team One is often called "The National Team" because they'll go anywhere inside the US to fight evil or injustice too strong for ordinary measures. They're not officially affiliated with the US government but the President has a golden phone to call them with, and in practice most everyone considers them America's Team. Current members are:
No longer members are:
New York City has its own team of superheroes, the New York Rangers, headquartered atop the Empire State Building since 1989.
Manhattan also has a solo hero, Spookshow, best described as a a cross between Spiderman (with his black costume) and Batman (think, "Marshall Rogers cape that eats people"), who wages a campaign of psychological terror against street-level criminals. He (possibly she) has several comic books, some cartoony, some quite dark and violent. Spookshow never uses guns and never harms innocents. While officially a wanted criminal, has saved enough cops' lives to be practically untouchable by New York's finest.
Pax, the UN's only superhero, operates out of UN HQ in Manhattan but doesn't have any adventures in the US itself, apparently. Mostly he's off doing good deeds and foiling evil ultranationalist plots to derail peace processes, and that sort of thing. His comics tend to have heavy moral or social lessons pounded into them.
Goldenwatch (or possibly Golden Watch, accounts differ) in San Francisco doesn't have a comic book of their own (or rather, they do, but even kids can tell it has no hooks to reality, and the writers change every few issues), so about all that's commonly known about them are 3 of the 4 team member names (Kohl, Svaha, and Pandora), that they never operate outside the bay area, and that its just maybe possible that ALL of them belong in the 40.
There are other solo heroes. Hurricane, in Orlando, Florida has his own comic book, and the sort of powers you would expect with a name like that.
Los Angeles has a B&W comic with the Adventures of Action Girl ("Trinity's Best Friend"). She doesn't have any superpowers ("a little judo, and I can draw a bit") but she's pretty clever, and can actually pull off looking cool in a costume with a skirt and a big A across the front of her jacket. She runs around LA and southern California on her motorcycle and tricks villains into defeating themselves or at least not beating her up. Trinity Herself doesn't appear in the comic book, apparently having some superpower related to summoning endless supplies of top-notch lawyers.