Risen Reef

Whenever Risen Reef or another Elemental you control enters, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped. If you don't put the card onto the battlefield, put it into your hand.

Mistwalker

Changeling (This card is every creature type.)
Flying
{1}{U}: Mistwalker gets +1/-1 until end of turn.

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Embodiment of Spring

{1}{G}, {T}, Sacrifice Embodiment of Spring: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Air-Cult Elemental

Flying
Whirlwind — When Air-Cult Elemental enters, return up to one other target creature to its owner's hand.

Fertilid

Fertilid enters with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from Fertilid: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

Aethersnipe

When Aethersnipe enters, return target nonland permanent to its owner's hand.
Evoke {1}{U}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: Mothdust Changeling gains flying until end of turn.

Wings of Velis Vel

Changeling (This card is every creature type.)
Until end of turn, target creature has base power and toughness 4/4, gains all creature types, and gains flying.

Thicket Crasher

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Other Elementals you control have trample.

Silverglade Elemental

When Silverglade Elemental enters, you may search your library for a Forest card, put that card onto the battlefield, then shuffle.

Wavesifter

Flying
When Wavesifter enters, investigate twice. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Evoke {G}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Woodland Changeling

Changeling (This card is every creature type.)

Guardian Gladewalker

Changeling (This card is every creature type.)
When Guardian Gladewalker enters, put a +1/+1 counter on target creature.

Universal Automaton

Healer of the Glade

When Healer of the Glade enters, you gain 3 life.

Boreal Elemental

Flying
Spells your opponents cast that target Boreal Elemental cost {2} more to cast.

Cloud Elemental

Flying
Cloud Elemental can block only creatures with flying.

Littjara Kinseekers

Changeling (This card is every creature type.)
When Littjara Kinseekers enters, if you control three or more creatures that share a creature type, put a +1/+1 counter on Littjara Kinseekers, then scry 1.

Leafkin Druid

{T}: Add {G}. If you control four or more creatures, add {G}{G} instead.

Walker of the Grove

When Walker of the Grove leaves the battlefield, create a 4/4 green Elemental creature token.
Evoke {4}{G} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Soul of the Rapids

Flying
Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Cloudkin Seer

Flying
When Cloudkin Seer enters, draw a card.

Floodhound

{3}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Masked Vandal

Changeling (This card is every creature type.)
When Masked Vandal enters, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.