Sacrifice a creature: Add {C}{C}.

{2}, {T}: Add {B} for each Swamp you control.

Whenever a creature enters the battlefield, you lose 1 life and add {B}.

Search your library for a card, put that card into your hand, then shuffle.

As an additional cost to cast this spell, sacrifice a creature.

Search your library for a card, put that card into your hand, then shuffle.

Avoidance -- Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Landfall -- Whenever a land enters the battlefield under your control, target player mills three cards.

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Search your library for a sorcery card, reveal it, then shuffle and put that card on top.

Search your library for a sorcery card, reveal it, then shuffle and put that card on top.

Sacrifice a creature: Add one mana of any color.

Landfall -- Whenever a land enters the battlefield under your control, each opponent mills three cards. (To mill a card, a player puts the top card of their library into their graveyard.)

When Spellseeker enters the battlefield, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Whenever you cast a spell you don't own, create a 3/3 black Demon creature token.

+1: Draw a card. For each opponent, exile up to one target instant or sorcery card from that player's graveyard and put a page counter on it.

-3: You may cast a spell from among cards in exile with page counters on them without paying its mana cost.

Tasha, the Witch Queen can be your commander.

At the beginning of your end step, if you didn't activate a loyalty ability of a planeswalker this turn, you lose 2 life.

{4}, {T}: For each planeswalker you control, you may activate one of its loyalty abilities once this turn as though none of its loyalty abilities have been activated this turn.

Each land is a Swamp in addition to its other land types.

Search your library for a card, then shuffle and put that card on top. You lose 2 life.