Boros Mastiff

Battalion — Whenever Boros Mastiff and at least two other creatures attack, Boros Mastiff gains lifelink until end of turn. (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Totem-Guide Hartebeest

When Totem-Guide Hartebeest enters, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Student of Ojutai

Whenever you cast a noncreature spell, you gain 2 life.

Akroan Hoplite

Whenever Akroan Hoplite attacks, it gets +X/+0 until end of turn, where X is the number of attacking creatures you control.

Axgard Cavalry

{T}: Target creature gains haste until end of turn.

Akroan Mastiff

Courier Griffin

Flying
When Courier Griffin enters, you gain 2 life.

Arabella, Abandoned Doll

Whenever Arabella, Abandoned Doll attacks, it deals X damage to each opponent and you gain X life, where X is the number of creatures you control with power 2 or less.

God-Favored General

Inspired — Whenever God-Favored General becomes untapped, you may pay {2}{W}. If you do, create two 1/1 white Soldier enchantment creature tokens.

Enduring Innocence

Lifelink
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.
When Enduring Innocence dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Viashino Firstblade

Haste
When Viashino Firstblade enters, it gets +2/+2 until end of turn.

Griffin Dreamfinder

Flying
When Griffin Dreamfinder enters, return target enchantment card from your graveyard to your hand.

Haazda Snare Squad

Whenever Haazda Snare Squad attacks, you may pay {W}. If you do, tap target creature an opponent controls.