Johann's Stopgap

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
This spell costs {2} less to cast if it's bargained.
Return target nonland permanent to its owner's hand. Draw a card.

Twisted Fealty

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
Create a Wicked Role token attached to up to one target creature. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1. When this Aura is put into a graveyard, each opponent loses 1 life.)

Najal, the Storm Runner

You may cast sorcery spells as though they had flash.
Whenever Najal, the Storm Runner attacks, you may pay {2}. If you do, when you next cast an instant or sorcery spell this turn, copy it. You may choose new targets for the copy.

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Johann, Apprentice Sorcerer

You may look at the top card of your library any time.
Once each turn, you may cast an instant or sorcery spell from the top of your library. (You still pay its costs. Timing rules still apply.)