Jace's Archivist

{U}, {T}: Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Thought Vessel

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

Oskar, Rubbish Reclaimer

This spell costs {1} less to cast for each different mana value among cards in your graveyard.
Whenever you discard a nonland card, you may cast it from your graveyard.

Counterspell

Rewind

Counter target spell. Untap up to four lands.

Feast of Sanity

Whenever you discard a card, Feast of Sanity deals 1 damage to any target and you gain 1 life.

Liliana's Caress

Whenever an opponent discards a card, that player loses 2 life.

Neutralize

Counter target spell.
Cycling {2} ({2}, Discard this card: Draw a card.)

Dark Deal

Each player discards all the cards in their hand, then draws that many cards minus one.

Dark Ritual

Skirge Familiar

Tolarian Winds

Discard all the cards in your hand, then draw that many cards.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Reliquary Tower

Arcane Signet

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

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

Island

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Sol Ring

Ad Nauseam

Reveal the top card of your library and put that card into your hand. You lose life equal to its mana value. You may repeat this process any number of times.

Bojuka Bog

Bojuka Bog enters the battlefield tapped.
When Bojuka Bog enters the battlefield, exile target player's graveyard.
{T}: Add {B}.

Drowned Catacomb

Drowned Catacomb enters the battlefield tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

Negate

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Dark Sphere

{T}, Sacrifice Dark Sphere: The next time a source of your choice would deal damage to you this turn, prevent half that damage, rounded down.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Wishclaw Talisman

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

Spellbook

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Megrim

Whenever an opponent discards a card, Megrim deals 2 damage to that player.

Teferi's Puzzle Box

At the beginning of each player's draw step, that player puts the cards in their hand on the bottom of their library in any order, then draws that many cards.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Sickening Dreams

As an additional cost to cast this spell, discard X cards.
Sickening Dreams deals X damage to each creature and each player.

Swamp

Faith of the Devoted

Whenever you cycle or discard a card, you may pay {1}. If you do, each opponent loses 2 life and you gain 2 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.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.