Soul Seal - 1B
When Seal of Souls enters the battlefield, return all exiled cards to their owner's graveyards.
Cards in graveyards can not be exiled.
This seems absolutely terrifying with Yawg Will.
Magnetic Resonance - 2RR
If Magnetic Resonance is in your opening hand, you may reveal it and exile a red card from your hand. If you do, begin the game with Magnetic Resonance on the battlefield.
Activated abilities of artifacts can't be activated.
Has significant preventative capability in the early game (like Force of Will does).
Heavily incentives one colour thus encouraging that colours broadened usage (like Force of Will does).
Already established as a valued effect in game by the use of Null Rod (similar to how Force of Will is comparable to Counterspell)