Bayou Groff

As an additional cost to cast this spell, sacrifice a creature or pay {3}.

Hunted Horror

Trample
When Hunted Horror enters, target opponent creates two 3/3 green Centaur creature tokens with protection from black.

Grim Wanderer

Flash
Tragic Backstory — Cast this spell only if a creature died this turn.

Sheltering Ancient

Trample
Cumulative upkeep—Put a +1/+1 counter on a creature an opponent controls. (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.)

Myr Superion

Spend only mana produced by creatures to cast this spell.

Arcane Signet

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

Varolz, the Scar-Striped

Each creature card in your graveyard has scavenge. The scavenge cost is equal to its mana cost. (Exile a creature card from your graveyard and pay its mana cost: Put a number of +1/+1 counters equal to that card's power on target creature. Scavenge only as a sorcery.)
Sacrifice another creature: Regenerate Varolz, the Scar-Striped.

Mulch

Reveal the top four cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.

Death's Shadow

Death's Shadow gets -X/-X, where X is your life total.

Witherbloom Command

Choose two —
• Target player mills three cards, then you return a land card from your graveyard to your hand.
• Destroy target noncreature, nonland permanent with mana value 2 or less.
• Target creature gets -3/-1 until end of turn.
• Target opponent loses 2 life and you gain 2 life.

Rampant Growth

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

Grisly Salvage

Reveal the top five cards of your library. You may put a creature or land card from among them into your hand. Put the rest into your graveyard.

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.

Golgari Signet

Lupine Prototype

Lupine Prototype can't attack or block unless a player has no cards in hand.

Sol Ring

Stitcher's Supplier

When Stitcher's Supplier enters or dies, mill three cards. (Put the top three cards of your library into your graveyard.)

Farseek

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