Plains

Neighborhood Guardian

Whenever another creature you control with power 2 or less enters, target creature you control gets +1/+1 until end of turn.

Resolute Reinforcements

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, create a 1/1 white Soldier creature token.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. This land deals 1 damage to you.

Mountain

Abraded Bluffs

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {R} or {W}.

Yotian Frontliner

Whenever this creature attacks, another target creature you control gets +1/+1 until end of turn.
Unearth {W} ({W}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Delney, Streetwise Lookout

Creatures you control with power 2 or less can't be blocked by creatures with power 3 or greater.
If an ability of a creature you control with power 2 or less triggers, that ability triggers an additional time.

Frantic Scapegoat

Haste
When this creature enters, suspect it. (It has menace and can't block.)
Whenever one or more other creatures you control enter, if this creature is suspected, you may suspect one of the other creatures. If you do, this creature is no longer suspected.

Gingerbrute

Haste (This creature can attack and {T} as soon as it comes under your control.)
{1}: This creature can't be blocked this turn except by creatures with haste.
{2}, {T}, Sacrifice this creature: You gain 3 life.

Arabella, Abandoned Doll

Whenever Arabella 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.

Knight-Errant of Eos

Convoke
When this creature enters, look at the top six cards of your library. You may reveal up to two creature cards with mana value X or less from among them, where X is the number of creatures that convoked this creature. Put the revealed cards into your hand, then shuffle.

Hop to It

Create three 1/1 white Rabbit creature tokens.

Inspiring Vantage

This land enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {W}.

Phoenix Chick

Flying, haste
This creature can't block.
Whenever you attack with three or more creatures, you may pay {R}{R}. If you do, return this card from your graveyard to the battlefield tapped and attacking with a +1/+1 counter on it.

Anim Pakal, Thousandth Moon

Whenever you attack with one or more non-Gnome creatures, put a +1/+1 counter on Anim Pakal, then create X 1/1 colorless Gnome artifact creature tokens that are tapped and attacking, where X is the number of +1/+1 counters on Anim Pakal.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.