Lore Seeker

At the beginning of your upkeep, you may put a charge counter on Aether Vial.
{T}: You may put a creature card with converted mana cost equal to the number of charge counters on Aether Vial from your hand onto the battlefield.

When Agent of Treachery enters the battlefield, gain control of target permanent.
At the beginning of your end step, if you control three or more permanents you don't own, draw three cards.

Remove Amulet of Quoz from your deck before playing if you're not playing for ante.
{T}, Sacrifice Amulet of Quoz: Target opponent may ante the top card of their library. If they don't, you flip a coin. If you win the flip, that player loses the game. If you lose the flip, you lose the game. Activate this ability only during your upkeep.

Target player draws three cards.

{T}: Add {W}.

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Sacrifice an artifact: Put a +1/+1 counter on Arcbound Ravager.
Modular 1

When Arcum's Astrolabe enters the battlefield, draw a card.
{1}, {T}: Add one mana of any color.

Ashkal Pillarstone enters the battlefield tapped.
{T}: Add {C} for each tapped artifact and/or creature you control.

Nonbasic lands don't untap during their controllers' untap steps.

Each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players discard cards and sacrifice creatures the same way.

Instant and sorcery spells you cast cost {1} less to cast.
Whenever a spell or ability you control counters a spell, you may draw a card. If you do, discard a card.

{T}: Draw two cards, then discard three cards.

You may pay {V}{V}{V} rather than pay the mana cost for instant and sorcery spells that you cast.

Each player's life total becomes the number of creatures they control.

{1}{G/P}, {T}, Sacrifice a creature: Search your library for a creature card with converted mana cost equal to 1 plus the sacrificed creature's converted mana cost, put that card onto the battlefield, then shuffle your library. Activate this ability only any time you could cast a sorcery.

{T}, Sacrifice Black Lotus: Add three mana of any one color.

You may exile a red card with converted mana cost X from your hand rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn.

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle your library.

At the beginning of each player's upkeep, that player sacrifices an artifact, creature, or land.

Whenever a nontoken creature is put into your graveyard from the battlefield, if Bridge from Below is in your graveyard, create a 2/2 black Zombie creature token.
When a creature is put into an opponent's graveyard from the battlefield, if Bridge from Below is in your graveyard, exile Bridge from Below.

Remove Bronze Tablet from your deck before playing if you're not playing for ante.
Bronze Tablet enters the battlefield tapped.
{4}, {T}: Exile Bronze Tablet and target nontoken permanent an opponent owns. That player may pay 10 life. If they do, put Bronze Tablet into its owner's graveyard. Otherwise, that player owns Bronze Tablet and you own the other exiled card.

When Burning-Tree Emissary enters the battlefield, add {R}{G}.

Take an extra turn after this one.

When Cauldron Familiar enters the battlefield, each opponent loses 1 life and you gain 1 life.
Sacrifice a Food: Return Cauldron Familiar from your graveyard to the battlefield.