So if I had to guess for an MCU Sinister Six it would be
- Vulture (introduced in homecoming)
- Scorpion (introduced in homecoming)
- Shocker (introduced in homecoming)
- Chameleon (tech introduced in Winter Soldier and hinted at in homecoming with identity theft related ads)
- Mysterio (for the sequel)
- Kraven (one of Tom's favorites, was going to be included in the Webb S6, rumors about his own movie, one of the few major Spidey villains not used yet, one of the original S6)
And none of these have been in the Raimi and Webb films (not counting Bruce Campbell potentially being Quintin Beck)