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.)

Goldmaw Champion

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

Trusted Pegasus

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

Circle of Protection: Green

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

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 Healer's Headdress to target creature you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Makindi Ox

Landfall — Whenever a land enters the battlefield under your control, tap target creature an opponent controls.

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.

Kor Hookmaster

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

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

Plains

Mardu Hordechief

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

Stonybrook Schoolmaster

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

Divine Verdict

Destroy target attacking or blocking creature.

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: Black

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

Seal of Cleansing

Sacrifice Seal of Cleansing: Destroy target artifact or enchantment.

Warded Battlements

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

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.)

Circle of Protection: Artifacts

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

Circle of Protection: Blue

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

Daybreak Charger

When Daybreak Charger enters the battlefield, target creature gets +2/+0 until end of 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.

Circle of Protection: Red

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

Palace Sentinels

When Palace Sentinels enters the battlefield, you become the monarch.

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.)

Valorous Steed

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

Circle of Protection: White

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

Gossamer Chains

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