msem-instigator

{T}: Add {C}.
{2}, {T}: Target creature gains haste until end of turn.

When Razorshell Marauder enters, you may sacrifice a land or exile a land card from your graveyard. When you do, target creature gets -1/-1 until end of turn and can't block this turn.

Flying
When Razorwing Champion enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Scry 2, then draw a card.
If you control a legendary permanent, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

At the beginning of your upkeep, Reality Collapse deals 1 damage to each opponent.
{2}{R}: Until end of turn, whenever an opponent is dealt noncombat damage, Reality Collapse deals that much damage to target creature that player controls.

Exile the top card of your library and up to one target permanent card from your graveyard. You may play cards exiled this way until the end of your next turn.
You may play an additional land this turn.

{T}: Target creature gains haste until end of turn.
{1}{R}, {T}, Sacrifice a Human: Create a token that's a copy of the sacrificed creature, except it's a 3/2 colorless Horror. It gains haste until end of turn. Activate only as a sorcery.

When Red Flower Assassin enters, destroy target creature.
Revive {5}{B} ({5}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Menace
Regal Dragoon gets +1/+1 as long as you control a legendary creature.

When Relentless Pathcutter enters, create a green Aura enchantment token named Enmity attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+0 and has trample.”
When Relentless Pathcutter dies, return it to its owner's hand.

Wanderlust — When you cast this spell, you may copy it if you control four or more differently named lands.
Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in a random order.

Counter target spell. Its controller draws a card.

Flying
Rezzal, the Loamfeaster gets +1/+1 for each nonland card exiled with it.
You may play lands exiled with Rezzal.
{1}{B/G}: Exile target card from an opponent's graveyard. Activate only outside of combat.

Flying, haste
Whenever Rhyolithic Hellkite attacks, you may sacrifice a land or exile a land card from your graveyard. If you do, put a +1/+1 counter on Rhyolithic Hellkite.

Target creature you control and each other creature with the same name as that creature get +3/+3 and gain trample until end of turn.

Target creature gets -2/-2 until end of turn.
{3}{B}, Exile Rift Splicing from your graveyard: Aetherize target creature card with mana value 3 or less in a graveyard. Activate only as a sorcery. (To aetherize, create a token that's a copy of it, then exile that token.)

Wanderlust — When Riftbreaker Mage dies, if you control four or more differently named lands, Riftbreaker Mage deals damage equal to its power to each opponent.

Flying, menace
When Riftkeeper Entity enters, discard your hand, then draw cards equal to the number of differently named lands you control.
{1}{R}, Discard Riftkeeper Entity: Create a tapped colorless land token named Fading Rift with “{T}, Sacrifice this land: Add one mana of any color.”

Put a +1/+1 counter on up to one target creature.
Draw a card.

At the beginning of your end step, aetherize target permanent you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Flash
When Rippling Water Arcanist enters, copy target instant or sorcery spell you control, then return it to its owner's hand. You may choose new targets for the copy.

Enchant creature
When Rising Tides enters, draw a card.
At the beginning of each upkeep, if enchanted creature is untapped, tap it.

As Ritual Preparations enters, choose a color.
You don't lose unspent mana of the chosen color as steps and phases end.

{7}{U}: Tap up to three target nonland permanents. This ability costs {2} less to activate if you control a legendary creature.