Invisible Woman

At the beginning of combat on your turn, if you've cast a noncreature spell this turn, create a 0/3 colorless Wall creature token with defender and reach.
Whenever you attack, you may pay {R}{G}{W}{U}. When you do, target creature gets +1/+0 until end of turn for each creature you control and can't be blocked this turn.

Human Torch

At the beginning of combat on your turn, if you've cast a noncreature spell this turn, Human Torch gains flying, double strike, and haste until end of turn.
Whenever Human Torch attacks, you may pay {R}{G}{W}{U}. If you do, until end of turn, whenever he deals combat damage to an opponent, he deals that much damage to each other opponent.

The Thing

Trample
At the beginning of combat on your turn, if you've cast a noncreature spell this turn, put four +1/+1 counters on The Thing.
Whenever The Thing attacks, you may pay {R}{G}{W}{U}. When you do, double the number of each kind of counter on any number of target permanents you control.

Mister Fantastic

Vigilance, reach
At the beginning of combat on your turn, if you've cast a noncreature spell this turn, draw a card.
{R}{G}{W}{U}, {T}: Copy target triggered ability you control twice. You may choose new targets for the copies.