Blasting Station

{T}, Sacrifice a creature: Blasting Station deals 1 damage to any target.
Whenever a creature enters, you may untap Blasting Station.

Arbor Elf

Devoted Druid

{T}: Add {G}.
Put a -1/-1 counter on Devoted Druid: Untap Devoted Druid.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Presence of Gond

Enchant creature
Enchanted creature has "{T}: Create a 1/1 green Elf Warrior creature token."

Plains

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.

Hall of the Bandit Lord

Hall of the Bandit Lord enters tapped.
{T}, Pay 3 life: Add {C}. If that mana is spent on a creature spell, it gains haste.

Genesis Wave

Reveal the top X cards of your library. You may put any number of permanent cards with mana value X or less from among them onto the battlefield. Then put all cards revealed this way that weren't put onto the battlefield into your graveyard.

Midnight Guard

Whenever another creature enters, untap Midnight Guard.

Scurry Oak

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Scurry Oak, you may create a 1/1 green Squirrel creature token.

Doomed Traveler

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

Forest

Moon-Blessed Cleric

Divine Intervention — When Moon-Blessed Cleric enters, you may search your library for an enchantment card, reveal it, then shuffle and put that card on top.

Vizier of Remedies

If one or more -1/-1 counters would be put on a creature you control, that many -1/-1 counters minus one are put on it instead.

Blossoming Defense

Target creature you control gets +2/+2 and gains hexproof until end of turn.

Quillspike

{B/G}, Remove a -1/-1 counter from a creature you control: Quillspike gets +3/+3 until end of turn.

Unnatural Predation

Target creature gets +1/+1 and gains trample until end of turn.

Order of the Stars

Defender (This creature can't attack.)
As Order of the Stars enters, choose a color.
Order of the Stars has protection from the chosen color.

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.