Anyone who can't pick out Thor after the commercials from 8 MC movies alone has been under a rock.

No hint for this guy.

Let's start easy... Who is this?

Eric Brooks/Blade got several movies before the MCU launch of Iron Man and the Avengers, then a recap with Deadpool & Wolverine.

Hint: anti-vampire vampire

Who is this?

Johnny Blaze brought Nick Cage to the MCU a year before Robert Downey Jr debuted as Iron Man.  Could you see trying to fit Ghost Rider into the Avengers?

What?  How many Marvel characters have burning skulls?

Natalia Romanova... the original MCU female avenger.  There's a blonde Widow as well, but the redhead is Natalia

Hint: Red Room.

Okay... did you know that Drax's real name is Arthur Douglas, and he was a real estate agent from Earth?  Really.  You can look it up.

Hint: Dave Bautista

Dane Whitman is the latest incarnation of the Black Knight and got a foreshadowing in the MC in The Eternals.

Hint: it's a family role.

Vision is a synthezoid with origins that change depending on which version you encounter, but most versions involve Ultron having a role.

Hint: Paul Bettany

Felicia Hardy/Black Cat is a thrill-seeking cat burglar who became a friend and occasional teammate of Peter Parker/Spidey.

Hint: Spidey ally.

Scott Lang became Ant-Man after Hank Pym retired from the superhero game.  

Hint: Pym particles.

Every Marvel fan knows as much about Steve Rogers as any comic superhero... ever... period.

Another gimme

Kitty Pryde/Shadowcat has been a Marvel mutant hero who has been on a number of teams and featured in many titles.

Hint: X-Men. Excalibur. Lockheed.

Clint Barton/Hawkeye is unfairly the punchline of Avenger jokes.  Same "powers" as Batman and Iron Man, but Clint's not a billionaire so he gets the fuzzy end of the marketing popsicle.

Hint: maybe you could confuse him for a DC hero... maybe.

Victor Creed/Sabertooth... one of the most frequently-used villains in the X-Man franchise.  Too bad it took until Deadpool & Wolverine for Logan to put Victor out of everyone's misery.

Hint: Wolverine foe.

Fantomex (no confirmed name but called "Charlie Cluster-7") is known as one of the great mystery characters of the Marvel multiverse.

Hint: Weapon XIII.  Possible mutant.  Self-proclaimed fake Frenchman.

Virginia "Pepper" Potts becoming Rescue is the natural result of Tony Stark's love interest having her character affect Stark design.

Hint: the color scheme.

Gambit/Remy LeBeau has always been a big character in the X-Men... so long as he's animated.  Live action has usually short-changed the character.

Hint: mutant who can blow sh*t up.

Kang may have been Nathaniel Richards (yes, you recognize the last name)... or maybe not.  And the MCU isn't helping by bringing in multiversal versions... OY!

Hint: incredibly confusing character.  

Brunnhilde/Valkyrie was the leader of Odin's shieldmaidens, and in the MCU is the current leader of the refugee Asgardians.

Hint: Asgardian.

Brian Braddock/Captain Britain is Betsy Braddock/Psylocke's younger twin brother, and has been teased but not yet appeared in the MCU.

Hint: twin brother to an X-Man.  Excalibur.

Either Anton or Ivan Vanko/Crimson Dynamo is a Russian scientist who created a suit which controls electromagnetism, intended to cause disruption to Stark Industries.

Hint: Russian foe of Iron Man

Not to be confused with Happy Hogan, Hogun is one of the Warriors Three with Volstagg and Fandrel.

Hint: Asgardian

Sam Wilson/Falcon (now Captain America since Steve Rogers' retirement) is central to the MCU's upcoming continuation of the Avengers franchise.

Hint: MCU, both movies and series.  Image is an early version.

Hint: he knows he's a comic character

Pietro Maximoff/Quicksilver is brother to Wanda/Scarlet Witch.  He's been both hero and villain, and in the MCU, a martyr.

Hint: brother of Wanda.

Emma Frost (formerly White Queen of the Hellfire Club) is a powerful telepath and acted as headmistress of a branch of the Xavier School in Massachusetts teaching Generation X.

Hint: good guy... bad guy... mutant... 

James Rhodes/War Machine (before being rebranded by Disney as Iron Patriot) is one of the few people Tony Stark trusts with Stark armor.

Hint: US military.

Bullseye (real name not confirmed) is an assassin and frequent foe of Daredevil.

Hint: 

Considered "the smartest man on Earth", Reed Richards gained his powers in the same cosmic radiation accident as the rest of the Fantastic Four.

Hint: think Stretch Armstrong

Though his first appearance was in 1966, King T'Challa/Black Panther was made famous by the late actor Chadwick Bowman for the MCU.

Hint: vibranium

Justine Hammer/Crimson Cowl is the daughter of Justin Hammer (yes, THAT Hammer) and depends on her techno-cape for her abilities.  She has yet to make an MCU appearance.

Hint: leader of the Masters of Evil.  Daughter of another Marvel villain.

Anyone who has seen any of the Guardians of the Galaxy movies knows this character.

Another gimme.

Crystal/Crystalia Amaquelin is princess of the Royal House of Attilan with enhanced physical capabilities and power over the elements.

Hint: species--inhomo supremis

Adam Warlock is a genetically-engineered being created to be "the perfect human" but became much more than that.  Expect to see more of him in the MCU.

Hint: "Him", created as a weapon, became a good guy in spite of their intentions.

Henry Camp/Bulldozer... ex-US Army (dishonorably discharged), criminal, and part of The Hood's criminal organization.

Hint: part of the Wrecking Crew.

Scott Summers/Cyclops is a founding member of the X-Men, brother of Havoc/Alex Summers, and (depending on the story line) occasionally husband of Jean Grey.

Hint: the visor is a giveaway.

Laura Kinney/Talon/X-23/Wolverine... first comic appearance in 2003 and now 2 MCU appearances.

Hint: a chick with adamantium talons and what... you need more of a hint?

Ororo Munroe/Storm is a long-time leader in the X-Men, one time queen of Wakanda and sometimes member of the Avengers (in the comics).

Hint: claustrophobic X-Man.  Goddess by aclamation.

Ronan is Supreme Accuser of the Kree Empire and foe of anyone who gets between him and his objective of the moment.

Hint: Kree bad-ass.

Jennifer Walters/She-Hulk is cousin of Bruce Banner and owes her Hulk-ness to an emergency blood transfusion from him.  She even got a mini-series but it was understandably not that well received.  Blame it on the writers.

No hint.  You don't need it.

Flint Marco/Sandman gained his sand-like state from Hammer Industries experimentation.  He got a fair deal from his movie portrayal by Thomas Hayden Church making him so sympathetic.

Hint: Spidey foe.

Jean Grey (Phoenix/Marvel Girl/Black Queen/Dark Phoenix) is considered one of, if not THE most powerful telepath in the Marvel universe, and as you can tell from her many names, she has a complicated history.

Hint: X-Men.

Matt Murdock/Daredevil... blind lawyer by day, vigilante hero by night... and a solid part of the Marvel universe since 1964.

Hint: the Man Without Fear.

Charles Xavier, center of the X-Men franchise and founder of the Xavier School.  Being portrayed by Patrick Stewart and James MacEvoy isn't too shabby, either.

No hints.

Ivan Vanko wasn't called Whiplash in Iron Man 2, but Anton Vanko (the same Vanko who was Crimson Dynamo) was Whiplash in the comics.  Both had issues with Tony Stark.

Hint: Mickey Rourke

Ben Grimm/The Thing was a test pilot for the USFA before their cosmic ray accident turned him into the clobberin' rock creature of the Fantastic Four.

Hint: "It's clobberin' time!"

Gwen Stacy/Ghost-Spider is a hero of Earth-65, but she was Peter Parker's girlfriend who was killed by Green Goblin on Earth-616, the primary Marvel universe of the comics.  I prefer her as a hero and would-be girlfriend of Miles Morales.

Hint: no MCU.

Mortimer Toynbee/Toad is frequent foe of the X-Men.  His name always sounded more like an Oxford tax accountant than a mutant villain, but that's just me.

Hint: Magneto henchman.

Madame Masque/Whitney Frost (born Giuletta Nefaria) is a major figure in the criminal underworld and occasional foe of Tony Stark and Peter Parker.

Hint: daughter of Count Nefaria.

Parker Robbins/The Hood (sometimes Lord Hood) gained his powers from a demonic hood and boots, using his powers to run a changing group of underworld villains.

Hint: it's 

I had to finish things so everyone gets a win on the last question.  You're welcome!

Hint... nah... just kidding.

Part 2 of Avengers... X-Men... Fantastic Four... Guardians of the Galaxy... the Defenders... heroes... villains... popular... obscure... all of them! Images are taken from a defunct Marvel online game and so might be considered "official".