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.)

Anafenza, Unyielding Lineage

Flash
First strike
Whenever another nontoken creature you control dies, Anafenza endures 2. (Put two +1/+1 counters on it or create a 2/2 white Spirit creature token.)

The Celestus

If it's neither day nor night, it becomes day as The Celestus enters.
{T}: Add one mana of any color.
{3}, {T}: If it's night, it becomes day. Otherwise, it becomes night. Activate only as a sorcery.
Whenever day becomes night or night becomes day, you gain 1 life. You may draw a card. If you do, discard a card.

Gandalf, White Rider

Vigilance
Whenever you cast a spell, creatures you control get +1/+0 until end of turn. Scry 1.
When Gandalf dies, you may put it into its owner's library fifth from the top.

Horn of the Mark

Whenever two or more creatures you control attack a player, look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Ravnica at War

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Zenith Chronicler

Whenever a player casts their first multicolored spell each turn, each other player draws a card.

Valkmira, Protector's Shield

If a source an opponent controls would deal damage to you or a permanent you control, prevent 1 of that damage.
Whenever you or another permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

Reidane, God of the Worthy

Flying, vigilance
Snow lands your opponents control enter tapped.
Noncreature spells your opponents cast with mana value 4 or greater cost {2} more to cast.

Reidane, God of the Worthy // Valkmira, Protector's Shield

Abzan Falconer

Outlast {W} ({W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has flying.

Kongming, "Sleeping Dragon"

Bovine Intervention

Destroy target artifact or creature. Its controller creates a 2/2 white Ox creature token.

Spear of Heliod

Creatures you control get +1/+1.
{1}{W}{W}, {T}: Destroy target creature that dealt damage to you this turn.

Dusk Legion Duelist

Vigilance
Whenever one or more +1/+1 counters are put on this creature, draw a card. This ability triggers only once each turn.

Blacksmith's Skill

Target permanent gains hexproof and indestructible until end of turn. If it's an artifact creature, it gets +2/+2 until end of turn.

Duty Beyond Death

As an additional cost to cast this spell, sacrifice a creature.
Creatures you control gain indestructible until end of turn. Put a +1/+1 counter on each creature you control. (Damage and effects that say "destroy" don't destroy those creatures.)

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Exemplar of Light

Flying
Whenever you gain life, put a +1/+1 counter on this creature.
Whenever you put one or more +1/+1 counters on this creature, draw a card. This ability triggers only once each turn.

Mangara of Corondor

God-Eternal Oketra

Double strike
Whenever you cast a creature spell, create a 4/4 black Zombie Warrior creature token with vigilance.
When God-Eternal Oketra dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.