Circle of Protection: Black

{1}: The next time a black source of your choice would deal damage to you this turn, prevent that damage.

Rider in Need

Create a 2/2 white Knight creature token with vigilance. (Then exile this card. You may cast the creature later from exile.)

Lonesome Unicorn

Lonesome Unicorn // Rider in Need

Healer's Headdress

Equipped creature gets +0/+2 and has "{T}: Prevent the next 1 damage that would be dealt to any target this turn."
{W}{W}: Attach this Equipment to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Gossamer Chains

Return this enchantment to its owner's hand: Prevent all combat damage that would be dealt by target unblocked creature this turn.

Seal of Cleansing

Sacrifice this enchantment: Destroy target artifact or enchantment.

Makindi Ox

Landfall — Whenever a land you control enters, tap target creature an opponent controls.

Circle of Protection: Blue

{1}: The next time a blue source of your choice would deal damage to you this turn, prevent that damage.

Keleth, Sunmane Familiar

Whenever a commander you control attacks, put a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)

Divine Verdict

Destroy target attacking or blocking creature.

Ray of Distortion

Destroy target artifact or enchantment.
Flashback {4}{W}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Daybreak Charger

When this creature enters, target creature gets +2/+0 until end of turn.

Valorous Steed

Vigilance (Attacking doesn't cause this creature to tap.)
When this creature enters, create a 2/2 white Knight creature token with vigilance.

Kor Hookmaster

When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Mardu Hordechief

Raid — When this creature enters, if you attacked this turn, create a 1/1 white Warrior creature token.

Plains

Noble Templar

Vigilance
Plainscycling {2} ({2}, Discard this card: Search your library for a Plains card, reveal it, put it into your hand, then shuffle.)

Goldmaw Champion

Boast — {1}{W}: Tap target creature. (Activate only if this creature attacked this turn and only once each turn.)

Benevolent Unicorn

If a spell would deal damage to a permanent or player, it deals that much damage minus 1 to that permanent or player instead.

Stonybrook Schoolmaster

Whenever this creature becomes tapped, you may create a 1/1 blue Merfolk Wizard creature token.

Circle of Protection: Red

{1}: The next time a red source of your choice would deal damage to you this turn, prevent that damage.

Warded Battlements

Defender (This creature can't attack.)
Attacking creatures you control get +1/+0.

Palace Sentinels

When this creature enters, you become the monarch.

Trusted Pegasus

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever this creature attacks, target attacking creature without flying gains flying until end of turn.

Lapse of Certainty

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Reprobation

Enchant creature
Enchanted creature loses all abilities and is a Coward creature with base power and toughness 0/1. (It keeps all supertypes but loses all other types and creature types.)

Circle of Protection: White

{1}: The next time a white source of your choice would deal damage to you this turn, prevent that damage.

Circle of Protection: Green

{1}: The next time a green source of your choice would deal damage to you this turn, prevent that damage.

Circle of Protection: Artifacts

{2}: The next time an artifact source of your choice would deal damage to you this turn, prevent that damage.