Rakdos Signet

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Golgari Signet

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Simic Signet

Yidris, Maelstrom Wielder

Trample
Whenever Yidris, Maelstrom Wielder deals combat damage to a player, as you cast spells from your hand this turn, they gain cascade. (When you cast the spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Gruul Signet

Dimir Signet

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Izzet Signet

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Exploration

You may play an additional land on each of your turns.