On a team with powerhouses such as Thor, Hulk, Blue Marvel and Scarlet Witch (sometimes), it is understandably hard to stand out in the Avengers, but this has not stopped Tony Stark from trying. The genius industrialist's intellect, tenacity and experience has enabled him to stand toe-to-toe next to his powerful allies as the armoured Iron Man.
Stark has developed numerous weapons such as the Bleeding Edge armour, Extremis, Hulkbuster and Godkiller suits of armour and he has used these world-shaking weapons to humble mighty foes such as Hulk, Ultron and even a Celestial over his six-decade career.
Unlike most heroes over at the Distinguished Competition, most Marvel do-gooders do not balk at the idea of murder and Tony is among this list.
True to his former career as a war profiteer, Iron Man is not above killing his opponents when the need arises. While he is not (always) a cold-blooded killer, the tech-based hero has been forced in situations where the only option was putting an end to his enemy's life. That said, there have been instances that have seen Stark off his foes in unusally brutal fashion.
10. Yellowjacket - Avengers: The Crossing
The Yellowjacket mantle originally belonged to Hank Pym for a while, but as with most superhero identities, it has been held by multiple individuals. A former (albeit, reluctant) criminal and member of the Masters of Evil, Rita eventually switched over to the side of the angels and joined the (futuristic) Guardians of the Galaxy following an alien invasion.
She spent a considerable amount of time with the extraterrestrial group before returning to Earth to warn the Avengers of a future disaster. Upon returning to the present, she found the heroes going toe-to-toe with a brainwashed Iron Man. Kang the Conqueror (under the guise of Immortus) tricked Tony into fighting his friends, and in the process the inventor killed an unsuspecting DeMara.
Fortunately, she was resurrected in the Chaos War but has not been seen since. This version of Yellowjacket was not as powerful as Hank Pym but she still used the Pym Particles to decent effect during her time as a villain and hero.
While DeMara is yet to appear in any Marvel media outside of the comics, at least a version of Yellowjacket (Pym) got the jump on Iron Man in the MCU's multiverse spanning "What If...?" animated series.