Hulk, Always Angry

Trample
When Hulk enters, destroy all artifacts.
Hulk attacks each combat if able.

Thor, Guardian of Midgard

Flying
Whenever a source you control deals noncombat damage to an opponent, you may exile that many cards from the top of your library. You may play those cards this turn.

Black Widow, Intel Expert

First strike
Whenever Black Widow deals combat damage to an opponent, you and that player each draw two cards.

Captain America, Unbowed

Flash
When Captain America enters, Soldiers and Heroes you control gain indestructible until end of turn.

Hawkeye, Trick Shot

First strike, reach
Whenever Hawkeye or another Hero you control enters, it deals damage equal to the number of Heroes you control to any target.

Ultron, Machine Overlord

Flying
Other Robots and Constructs you control get +2/+2.

Thanos, Death's Consort

Lifelink
Whenever another creature dies, put a +1/+1 counter on Thanos.

M.O.D.O.K., Evil Intellect

Flying
Whenever you draw your second card each turn, target opponent sacrifices a nontoken creature of their choice.

Flame On!

Put X +1/+1 counters on target creature, where X is the number of noncreature, nonland cards in your graveyard. It gains flying until end of turn.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Absorbing Man and Titania

Double all damage that creature sources you control would deal.

Abomination, Irradiated Brute

Trample
Whenever a Gamma or Villain you control deals combat damage to a player, put that many +1/+1 counters on Abomination.

Loki, God of Lies

Whenever you cast a spell that targets only a single creature, gain control of that creature until end of turn. If it's your turn, untap that creature and it gains haste until end of turn.

Fall to Earth

Exile target creature. Each player gains 3 life.
Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Hawkeye, Clint Barton

Vigilance (Attacking doesn't cause this creature to tap.)

Franklin Richards, Ascendant

At the beginning of combat on your turn, if you've cast a noncreature spell this turn, discover 6. (Exile cards from the top of your library until you exile a nonland card with mana value 6 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Iconic Shield

Equipped creature gets +1/+2 and has "Whenever this creature attacks, another target attacking creature gains indestructible until end of turn." (Damage and effects that say "destroy" don't destroy it.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Marvel Super Heroes Commander