What active passives are there?

Unknown

I know there must be a list around here somewhere but I could not find one?

Also what are the best team-ups to take advantage of the active passives?

Cabol

I could be mistaken, but I think only Dr. Doom has an active/passive with Diabolic Plot.

Unknown

Doom is the only one with a true passive -> active.

You might also be thinking of abilities that rely on special tiles like Mystique's Purple and Colossus Yellow an active/passive, though in the reverse order of Doom (passive/active). Other ones might include:
Invisible Woman's invisibility,
Punisher's Molotov,
BP's Defensive Grid,
Starlord ?
...