Arachnoform

Enchant creature
Enchanted creature gets +2/+2, has reach, and is every creature type.

Arachnogenesis

Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.

Arcus Acolyte

Reach, lifelink
Outlast {G/W} ({G/W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each other creature you control without a +1/+1 counter on it has outlast {G/W}.

Arachnoid Adaptation

Target creature gets +2/+2 and gains reach until end of turn. Untap it.

Avatar of the Resolute

Reach, trample
Avatar of the Resolute enters with a +1/+1 counter on it for each other creature you control with a +1/+1 counter on it.

Byrke, Long Ear of the Law

Vigilance
When Byrke, Long Ear of the Law enters, put a +1/+1 counter on each of up to two target creatures.
Whenever a creature you control with a +1/+1 counter on it attacks, double the number of +1/+1 counters on it.

Arasta of the Endless Web

Reach
Whenever an opponent casts an instant or sorcery spell, create a 1/2 green Spider creature token with reach.

Druid of the Spade

As long as you control a token, Druid of the Spade gets +2/+0 and has trample.

Arbor Armament

Put a +1/+1 counter on target creature. That creature gains reach until end of turn. (It can block creatures with flying.)

Finneas, Ace Archer

Vigilance, reach
Whenever Finneas, Ace Archer attacks, put a +1/+1 counter on each other creature you control that's a token or a Rabbit. Then if creatures you control have total power 10 or greater, draw a card.

Pawpatch Recruit

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Trample
Whenever a creature you control becomes the target of a spell or ability an opponent controls, put a +1/+1 counter on target creature you control other than that creature.

Hare Raising

Target creature you control gains vigilance and gets +X/+X until end of turn, where X is the number of creatures you control.

Pollen-Shield Hare

Pollen-Shield Hare // Hare Raising

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Regal Bunnicorn

Regal Bunnicorn's power and toughness are each equal to the number of nonland permanents you control.

Jacked Rabbit

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)
Whenever Jacked Rabbit attacks, create a number of 1/1 white Rabbit creature tokens equal to Jacked Rabbit's power.

Claim Jumper

Vigilance
When Claim Jumper enters, if an opponent controls more lands than you, you may search your library for a Plains card and put it onto the battlefield tapped. Then if an opponent controls more lands than you, repeat this process once. If you search your library this way, shuffle.

Burrowguard Mentor

Trample
Burrowguard Mentor's power and toughness are each equal to the number of creatures you control.