Mystical Dispute

This spell costs {2} less to cast if it targets a blue spell.
Counter target spell unless its controller pays {3}.

Archon of Cruelty

Flying
Whenever Archon of Cruelty enters or attacks, target opponent sacrifices a creature or planeswalker of their choice, discards a card, and loses 3 life. You draw a card and gain 3 life.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Faithful Mending

You gain 2 life, draw two cards, then discard two cards.
Flashback {1}{W}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Collective Brutality

Escalate—Discard a card. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Target opponent reveals their hand. You choose an instant or sorcery card from it. That player discards that card.
• Target creature gets -2/-2 until end of turn.
• Target opponent loses 2 life and you gain 2 life.

Godless Shrine

({T}: Add {W} or {B}.)
As Godless Shrine enters, you may pay 2 life. If you don't, it enters tapped.

Watery Grave

({T}: Add {U} or {B}.)
As Watery Grave enters, you may pay 2 life. If you don't, it enters tapped.

Island

Founding the Third Path

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — You may cast an instant or sorcery spell with mana value 1 or 2 from your hand without paying its mana cost.
II — Target player mills four cards.
III — Exile target instant or sorcery card from your graveyard. Copy it. You may cast the copy.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Glacial Fortress

Glacial Fortress enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Stony Silence

Activated abilities of artifacts can't be activated.

Tainted Indulgence

Draw two cards. Then discard a card unless there are five or more mana values among cards in your graveyard.

Persist

Return target nonlegendary creature card from your graveyard to the battlefield with a -1/-1 counter on it.

Drowned Catacomb

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

Lingering Souls

Create two 1/1 white Spirit creature tokens with flying.
Flashback {1}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Plains

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.

Swamp

March of Otherworldly Light

As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile target artifact, creature, or enchantment with mana value X or less.

Teferi, Time Raveler

Each opponent can cast spells only any time they could cast a sorcery.
+1: Until your next turn, you may cast sorcery spells as though they had flash.
−3: Return up to one target artifact, creature, or enchantment to its owner's hand. Draw a card.

Prismatic Ending

Converge — Exile target nonland permanent if its mana value is less than or equal to the number of colors of mana spent to cast this spell.

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Terastodon

When Terastodon enters, you may destroy up to three target noncreature permanents. For each permanent put into a graveyard this way, its controller creates a 3/3 green Elephant creature token.

Hallowed Moonlight

Until end of turn, if a creature would enter and it wasn't cast, exile it instead.
Draw a card.

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Unmarked Grave

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

Raffine's Tower

({T}: Add {W}, {U}, or {B}.)
Raffine's Tower enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Unburial Rites

Return target creature card from your graveyard to the battlefield.
Flashback {3}{W} (You may cast this card from your graveyard for its flashback cost. Then exile it.)