Tireless Tracker

Landfall — Whenever a land you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on Tireless Tracker.

Avenger of Zendikar

When Avenger of Zendikar enters, create a 0/1 green Plant creature token for each land you control.
Landfall — Whenever a land you control enters, you may put a +1/+1 counter on each Plant creature you control.

Guardian Project

Whenever a nontoken creature you control enters, if it doesn't have the same name as another creature you control or a creature card in your graveyard, draw a card.

Peregrine Drake

Flying
When Peregrine Drake enters, untap up to five lands.

God-Eternal Oketra

Double strike
Whenever you cast a creature spell, create a 4/4 black Zombie Warrior creature token with vigilance.
When God-Eternal Oketra dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Dream Stalker

When Dream Stalker enters, return a permanent you control to its owner's hand.

Chulane, Teller of Tales

Vigilance
Whenever you cast a creature spell, draw a card, then you may put a land card from your hand onto the battlefield.
{3}, {T}: Return target creature you control to its owner's hand.

Spellseeker

When Spellseeker enters, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Elvish Mystic

Solemn Simulacrum

When Solemn Simulacrum enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When Solemn Simulacrum dies, you may draw a card.

Kor Skyfisher

Flying
When Kor Skyfisher enters, return a permanent you control to its owner's hand.

Wood Elves

When Wood Elves enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Springbloom Druid

When Springbloom Druid enters, you may sacrifice a land. If you do, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Mystic Snake

Flash
When Mystic Snake enters, counter target spell.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Temur Sabertooth

{1}{G}: You may return another creature you control to its owner's hand. If you do, Temur Sabertooth gains indestructible until end of turn.

Whitemane Lion

Flash
When Whitemane Lion enters, return a creature you control to its owner's hand.

Shrieking Drake

Flying
When Shrieking Drake enters, return a creature you control to its owner's hand.

Birds of Paradise

Mother of Runes

{T}: Target creature you control gains protection from the color of your choice until end of turn.

Llanowar Elves

Elvish Visionary

When Elvish Visionary enters, draw a card.

Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Coiling Oracle

When Coiling Oracle enters, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.