I know the origins and even small moments of their lives which reveal even more personal details of Cap, Tony, Thor, Loki, Natasha, Clint, Spidey, Vulture, Strange, Quill, Rocket, Gamora and Nebula, Yondu, Drax, Bucky, Wanda, Pietro, Bruce, Scott, Hank, Hope, T'Challa, Danvers, Fury, and even Thanos I think that is more than 7.
That's the issue it wasn't just they concentrated on that 7 in the films it was they didn't bother to develop the rest.