9) Ultimate Six
Ultimate Six was set in the Ultimate Marvel Universe and saw the Sinister Six brought together by the Green Goblin after he and his fellow villains broke out of S.H.I.E.L.D. custody. The twist here is that they forced Spider-Man to join them as they attacked the White House, and the wall-crawler actually spent pretty much the entirety of this story unmasked and at their mercy.
It sounds like Drew Goddard’s Sinister Six movie was going to take things in a similar direction, and if Marvel Studios resurrects that now scrapped spinoff (both that and Venom were ditched earlier this year), then heading in this direction would be very cool.
A big reason for that is because The Avengers end up factoring into the final act, giving Spider-Man some much needed backup as he goes to war with this team of villains in front of the White House.