Mana Severance

Search your library for any number of land cards, exile them, then shuffle.

Rampant Growth

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

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Selective Memory

Search your library for any number of nonland cards, exile them, then shuffle.

Opposition Agent

Flash
You control your opponents while they're searching their libraries.
While an opponent is searching their library, they exile each card they find. You may play those cards for as long as they remain exiled, and you may spend mana as though it were mana of any color to cast them.

Farseek

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

Archelos, Lagoon Mystic

As long as Archelos, Lagoon Mystic is tapped, other permanents enter tapped.
As long as Archelos is untapped, other permanents enter untapped.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Storm Cauldron

Each player may play an additional land during each of their turns.
Whenever a land is tapped for mana, return it to its owner's hand.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Hullbreacher

Flash
If an opponent would draw a card except the first one they draw in each of their draw steps, instead you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Hive Mind

Whenever a player casts an instant or sorcery spell, each other player copies that spell. Each of those players may choose new targets for their copy.

Villainous Wealth

Target opponent exiles the top X cards of their library. You may cast any number of spells with mana value X or less from among them without paying their mana costs.

Kodama's Reach

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.