Llanowar Elves

Tyvar, Jubilant Brawler

You may activate abilities of creatures you control as though those creatures had haste.
+1: Untap up to one target creature.
−2: Mill three cards, then you may return a creature card with mana value 2 or less from your graveyard to the battlefield.

Elvish Mystic

Gyruda, Doom of Depths

Companion — Your starting deck contains only cards with even mana values. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
When Gyruda enters, each player mills four cards. Put a creature card with an even mana value from among the milled cards onto the battlefield under your control.

Bounding Krasis

Flash (You may cast this spell any time you could cast an instant.)
When Bounding Krasis enters, you may tap or untap target creature.

Prime Speaker Vannifar

{T}, Sacrifice another creature: Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.

Samut, Voice of Dissent

Flash
Double strike, vigilance, haste
Other creatures you control have haste.
{W}, {T}: Untap another target creature.

Breaching Hippocamp

Flash (You may cast this spell any time you could cast an instant.)
When Breaching Hippocamp enters, untap another target creature you control.

Corridor Monitor

When Corridor Monitor enters, untap target artifact or creature you control.

Atraxa, Grand Unifier

Flying, vigilance, deathtouch, lifelink
When Atraxa, Grand Unifier enters, reveal the top ten cards of your library. For each card type, you may put a card of that type from among the revealed cards into your hand. Put the rest on the bottom of your library in a random order. (Artifact, battle, creature, enchantment, instant, land, planeswalker, and sorcery are card types.)