Omnath, Locus of the Roil

When Omnath, Locus of the Roil enters, it deals damage to any target equal to the number of Elementals you control.
Landfall — Whenever a land you control enters, put a +1/+1 counter on target Elemental you control. If you control eight or more lands, draw a card.

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.

Creeping Trailblazer

Other Elementals you control get +1/+0.
{2}{R}{G}: Creeping Trailblazer gets +1/+1 until end of turn for each Elemental you control.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Undergrowth Champion

If damage would be dealt to Undergrowth Champion while it has a +1/+1 counter on it, prevent that damage and remove a +1/+1 counter from Undergrowth Champion.
Landfall — Whenever a land you control enters, put a +1/+1 counter on Undergrowth Champion.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Khalni Heart Expedition

Landfall — Whenever a land you control enters, you may put a quest counter on Khalni Heart Expedition.
Remove three quest counters from Khalni Heart Expedition and sacrifice it: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Sylvan Awakening

Until your next turn, all lands you control become 2/2 Elemental creatures with reach, indestructible, and haste. They're still lands.

Thicket Crasher

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

Grove Rumbler

Trample
Landfall — Whenever a land you control enters, Grove Rumbler gets +2/+2 until end of turn.

Flamekin Harbinger

When Flamekin Harbinger enters, you may search your library for an Elemental card, reveal it, then shuffle and put that card on top.

Incandescent Soulstoke

Other Elemental creatures you control get +1/+1.
{1}{R}, {T}: You may put an Elemental creature card from your hand onto the battlefield. That creature gains haste until end of turn. Sacrifice it at the beginning of the next end step.

Ashaya, Soul of the Wild

Ashaya, Soul of the Wild's power and toughness are each equal to the number of lands you control.
Nontoken creatures you control are Forest lands in addition to their other types. (They're still affected by summoning sickness.)

Retreat to Kazandu

Landfall — Whenever a land you control enters, choose one —
• Put a +1/+1 counter on target creature.
• You gain 2 life.

Temur Ascendancy

Creatures you control have haste.
Whenever a creature you control with power 4 or greater enters, you may draw a card.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Brushfire Elemental

Haste
Brushfire Elemental can't be blocked by creatures with power 2 or less.
Landfall — Whenever a land you control enters, Brushfire Elemental gets +2/+2 until end of turn.