When I first started watching Marvel, it was Hawkeye. He's still one of my favorites, but the guy that took the top spot is Doctor Strange. I don't know how, or when it happened but I just love that guy (speaking as someone who's solely MCU fan. Haven't read any comics). I just.. idk, all of his versions are cool
Some of my other favorites include:
Bucky, Sam Wilson, Natasha, Venom, Loki, Mobius, Black Panther (T'Challa more-so), Moon Knight, and Zemo
EDIT: I forgot Jack Russell ;-; WWBN was so fun ^^