7. Captain America
The Star-Spangled Man With A Plan is one of the greatest heroes in the Marvel Cinematic Universe. Heck, he might be the greatest hero in the Marvel Cinematic Universe.
Steve Rogers was always a hero. Long before he battling Hydra and dealing with alien invasions, he was standing up for people, protecting others, and getting into fights he probably couldn't win but doing it anyway because it was the right thing to do. Those are pretty solid foundations for a superhero, and as we've said many times on this list, the best heroes can be the mortal ones.
However, Steve's capabilities were enhanced by the Super Soldier Serum. With that, he could enact those desires of looking out for others, and follow through on them, defeating any and all threats that came his way.
While Steve's lovable catchphrase to his opponents was always "I can do this all day", he literally could do just that when he took the Serum. His stamina is second-to-none in the MCU, as he's able to engage in high levels of hand-to-hand combat without getting too worn out too quickly. Part of the reason for that is the fact that he's incredibly durable, as he can withstand large onslaughts of punishment and still come back fighting.
Speaking of fighting, Cap is among the very best to do it. Not only can he throw some hard-hitting punches, he can outfight almost anyone that comes his way, taking the Winter Soldier to the limit and even momentarily outpowering an Infinity Gauntlet-empowered Thanos. Throw in the shield (which can literally be thrown with extreme power due to his enhanced strength) and good luck beating Captain America on his worst day, nevermind his best.
Thor and Hulk might have an ongoing debate about who the Strongest Avenger is, but Steve Rogers would also be a worthy candidate to hold that title. He is, after all, worthy.