Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Diabolic Intent

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.

Vile Entomber

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When this creature enters, search your library for a card, put that card into your graveyard, then shuffle.

Hall of the Bandit Lord

Hall of the Bandit Lord enters tapped.
{T}, Pay 3 life: Add {C}. If that mana is spent on a creature spell, it gains haste.

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Triskelion

Triskelion enters with three +1/+1 counters on it.
Remove a +1/+1 counter from Triskelion: It deals 1 damage to any target.

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Entomb

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

Jet Medallion

Black spells you cast cost {1} less to cast.

Skirge Familiar

Oriq Loremage

{T}: Search your library for a card, put it into your graveyard, then shuffle. If it's an instant or sorcery card, put a +1/+1 counter on Oriq Loremage.

Walking Ballista

Walking Ballista enters with X +1/+1 counters on it.
{4}: Put a +1/+1 counter on Walking Ballista.
Remove a +1/+1 counter from Walking Ballista: It deals 1 damage to any target.

Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Wishclaw Talisman

This artifact enters with three wish counters on it.
{1}, {T}, Remove a wish counter from this artifact: Search your library for a card, put it into your hand, then shuffle. An opponent gains control of this artifact. Activate only during your turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Sceptre of Eternal Glory

{T}: Add one mana of any color.
{T}: Add three mana of any one color. Activate only if you control three or more lands with the same name.

Voltaic Construct

Unmarked Grave

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

The Underworld Cookbook

{T}, Discard a card: Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
{4}, {T}, Sacrifice The Underworld Cookbook: Return target creature card from your graveyard to your hand.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Stitcher's Supplier

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

Gilded Lotus

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Cabal Coffers

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

Necrotic Ooze

As long as Necrotic Ooze is on the battlefield, it has all activated abilities of all creature cards in all graveyards.

Mesmeric Orb

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

Farmstead Gleaner

Farmstead Gleaner doesn't untap during your untap step.
{2}, {Q}: Put a +1/+1 counter on Farmstead Gleaner. ({Q} is the untap symbol.)

Peer into the Abyss

Target player draws cards equal to half the number of cards in their library and loses half their life. Round up each time.

Animate Dead

Enchant creature card in a graveyard
When Animate Dead enters, if it's on the battlefield, it loses "enchant creature card in a graveyard" and gains "enchant creature put onto the battlefield with Animate Dead." Return enchanted creature card to the battlefield under your control and attach Animate Dead to it. When Animate Dead leaves the battlefield, that creature's controller sacrifices it.
Enchanted creature gets -1/-0.

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

Conqueror's Flail

Equipped creature gets +1/+1 for each color among permanents you control.
As long as Conqueror's Flail is attached to a creature, your opponents can't cast spells during your turn.
Equip {2}

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Vampiric Tutor

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

Ashnod's Altar

Krark-Clan Ironworks

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Urza's Saga gains "{T}: Add {C}."
II — Urza's Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This creature gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Demonic Tutor

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

Phyrexian Devourer

When Phyrexian Devourer's power is 7 or greater, sacrifice it.
Exile the top card of your library: Put X +1/+1 counters on Phyrexian Devourer, where X is the exiled card's mana value.

Grim Tutor

Search your library for a card, put that card into your hand, then shuffle. You lose 3 life.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Beacon of Unrest

Put target artifact or creature card from a graveyard onto the battlefield under your control. Shuffle Beacon of Unrest into its owner's library.

Swamp

Palladium Myr

Pili-Pala

Flying
{2}, {Q}: Add one mana of any color. ({Q} is the untap symbol.)

Trazyn the Infinite

Deathtouch
Prismatic Gallery — As long as Trazyn the Infinite is on the battlefield, it has all activated abilities of all artifact cards in your graveyard.

Kuldotha Forgemaster

{T}, Sacrifice three artifacts: Search your library for an artifact card, put it onto the battlefield, then shuffle.

Patchwork Gnomes

Discard a card: Regenerate Patchwork Gnomes. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Imperial Seal

Arcane Signet

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

Golem Artisan

{2}: Target artifact creature gets +1/+1 until end of turn.
{2}: Target artifact creature gains your choice of flying, trample, or haste until end of turn.

Sculpting Steel

You may have Sculpting Steel enter as a copy of any artifact on the battlefield.

Putrid Imp

Discard a card: Putrid Imp gains flying until end of turn.
Threshold — As long as seven or more cards are in your graveyard, Putrid Imp gets +1/+1 and can't block.

Sol Ring

Vault of Whispers

Rings of Brighthearth

Whenever you activate an ability, if it isn't a mana ability, you may pay {2}. If you do, copy that ability. You may choose new targets for the copy.

Their Name Is Death

Mystic Forge

You may look at the top card of your library any time.
You may cast artifact spells and colorless spells from the top of your library.
{T}, Pay 1 life: Exile the top card of your library.

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Staff of Domination

{1}: Untap Staff of Domination.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Dark Ritual

Codex Shredder

{T}: Target player mills a card. (They put the top card of their library into their graveyard.)
{5}, {T}, Sacrifice Codex Shredder: Return target card from your graveyard to your hand.