msem-instigator

This spell costs {1}{B} less to cast if it targets a green or white permanent.
Destroy target creature or planeswalker.

This spell costs {1}{U} less to cast if it targets a red or green spell.
Counter target spell.
Draw a card.

This spell costs {R} less to cast if it targets a white or blue permanent.
Once Scarred deals 4 damage to target creature or planeswalker.

This spell costs {W} less to cast if it targets a black or red permanent.
Exile target nonland permanent with mana value 3 or less.

When Ophidian Oracle enters the battlefield, draw a card, then abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)
Recite {2}{G}{G} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters the battlefield or if it would leave the battlefield.)

When Over the Horizon enters the battlefield, scry 1.
{T}: Add {C}.
{1}, {T}: Return Over the Horizon to its owner's hand.

{1}, {T}, Pay 1 life: Add one mana of any color. Put a charge counter on Paradox Rings.
{T}, Remove three charge counters from Paradox Rings and sacrifice it: Draw a card.

Players can't pay alternative costs to cast spells. (Casting a spell without paying its mana cost is an alternative cost.)

Enchant creature
Enchanted creature gets +1/+0 and has haste.
Once each turn, when enchanted creature becomes tapped, you may add {R}{R}. Until end of turn, you don't lose this mana as steps and phases end.

Whenever a player gains life, that player loses 2 life.

At the beginning of your upkeep, exile the top card of each of your libraries.
Put X cards exiled with Possibility Matrix on the bottom of their owner's library: You may cast a nonland card exiled with Possibility Matrix with mana value X or less without paying its mana cost.

At the beginning of each upkeep, if it's an extra turn, end the turn.
If a player would search a library, that player searches the top four cards of that library instead.

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color that land could produce.

Flash
When Rahit's Prodigy enters the battlefield, return target instant or sorcery card from your graveyard to your hand, then discard a card.

Archive 5 (As this enters the battlefield, shuffle the top five cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
At the beginning of your upkeep, put the top card of any of your libraries on the bottom of the archived library, then you may put any card in the archived library on top of the archived library.

[+1]: Each player may draw a card. For each opponent who does, put a loyalty counter on Rahit.
[–1]: Each player draws three cards, then puts two cards from their hand on top of their library in any order.
[–6]: You get an emblem with “Discard a card with mana value X: Counter target spell with mana value X or less.”

Counter target spell unless its controller pays {1}. If they do, draw a card.

Starting with you, each player either passes or reveals the top card of their library. Each player that revealed a card this way pays life equal to its mana value. If a player can't, that player passes. Then each player who hasn't passed yet puts that card into their hand. Repeat this process until each player has passed.

Choose target player. Until end of turn, if a spell or ability that player controls would cause them to draw a card, each of their opponents draws a card instead.

Lifelink
Whenever Repent, Daughter of Fallacy blocks or becomes blocked, it deals 3 damage to any target.

Artifacts and lands enter the battlefield tapped.

({T}: Add {R}.)
Rousing Rubble enters the battlefield tapped.
Double strike
{2}{R}{R}: Rousing Rubble becomes a creature in addition to its other types until end of turn.

Trample
Rubble Tender's power and toughness are each equal to the number of land cards in your graveyard.
At the beginning of your upkeep, sacrifice a land, then search your library for up to two land cards, put them onto the battlefield tapped, then shuffle.

Enchant land
Whenever enchanted land becomes tapped, scry 1.
Enchanted land has “{G}, {T}: Each player reveals the top card of their library. Each player that revealed a land card this way may put that card into their hand.”