Kamahl's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Until end of turn, any number of target lands you control become 1/1 Elemental creatures with vigilance, indestructible, and haste. They're still lands.
• Choose target creature you don't control. Each creature you control deals damage equal to its power to that creature.

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}

Sylvan Advocate

Vigilance
As long as you control six or more lands, this creature and land creatures you control get +2/+2.

Sylvan Awakening

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

Staff of Titania

Equipped creature gets +X/+X, where X is the number of Forests you control.
Whenever equipped creature attacks, create a 1/1 green Forest Dryad land creature token. (It's affected by summoning sickness.)
Equip {3}

Mossborn Hydra

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
This creature enters with a +1/+1 counter on it.
Landfall — Whenever a land you control enters, double the number of +1/+1 counters on this creature.

Jyoti, Moag Ancient

When Jyoti enters, create a 1/1 green Forest Dryad land creature token for each time you've cast your commander from the command zone this game. (They're affected by summoning sickness.)
At the beginning of each combat, land creatures you control get +X/+X until end of turn, where X is Jyoti's power.

Titania, Nature's Force

You may play Forests from your graveyard.
Whenever a Forest you control enters, create a 5/3 green Elemental creature token.
Whenever an Elemental you control dies, you may mill three cards.

Halimar Tidecaller

When this creature enters, you may return target card with awaken from your graveyard to your hand.
Land creatures you control have flying.