4* Nova 5/3/5 4* Howard the Duck 5/3/5 3* Scarlet Witch 5/3/5 Rainbow team set up to get Howard invisible often and early. Switch generates purple to get Howard's Duck, Duck loose going, Hex Bolt can also be a low cost way to get that last couple of AP. Nova provides strikes to beef up Duck, Duck Loose and keeps anyone who negates invisibility airborne. Howard does damage passively with purple and removes strikes while stunning w/ blue and once Nova has gotten strikes out green creates devastating cascades. . I love this team for boss battles. And it is a great troll team in Season SHIELD Simulator.
EDITED - to fit 500 character constraint.
Iron Fist might be the best of that tier, with his constant damage and the cheap purple that either manipulates the board or deals huge damage. Cap takes care of rest of the colors. He requires a lot of AP to get going, but when he does, he is a heavy hitting, stun inducing, enemy tile ridding fighting machine. Luke supports the team with his powerful protect tile. He also can put the black AP to some good use once Danny is done with it, while also providing an excellent alternative for yellow.