Energy Arc

Untap any number of target creatures. Prevent all combat damage that would be dealt to and dealt by those creatures this turn.

Angus Mackenzie

{G}{W}{U}, {T}: Prevent all combat damage that would be dealt this turn. Activate only before the combat damage step.

Dolmen Gate

Prevent all combat damage that would be dealt to attacking creatures you control.

Angelic Exaltation

Whenever a creature you control attacks alone, it gets +X/+X until end of turn, where X is the number of creatures you control.

Constant Mists

Buyback—Sacrifice a land. (You may sacrifice a land in addition to any other costs as you cast this spell. If you do, put this card into your hand as it resolves.)
Prevent all combat damage that would be dealt this turn.