msem-instigator

First strike
Creatures you control attacking cause abilities of that creature to trigger as though it entered.

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.

This spell costs {1} less to cast for each artifact and enchantment you control.
Reveal the top seven cards of your library. Put any number of noncreature, nonland cards from among them into your hand and the rest of the revealed cards into your graveyard.

This spell costs {2} less to cast and may be cast as though it had flash if an opponent searched their library this turn.
When Ridge Warden enters, exile another target nonland permanent with mana value 4 or less until Ridge Warden leaves the battlefield.

Trample
Rift Prowler enters with X +1/+1 counters on it, where X is your fealty to Forests. (Each Forest you control counts towards your fealty to Forests.)

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.”

Other Humans you control get +1/+1.
Whenever Righteous Chaplain or another Human you control enters, tap target creature an opponent controls.

When Rigid Conformist enters, for each {W} spent to cast it, create a 1/1 white Human creature token.
Each creature you control gets +2/+2 if you control another creature with the same name as that creature.

Flying
Whenever Rimebreath Tyrant attacks, you may discard a card. When you do, tap target creature. It doesn't untap during its controller's next untap step.

This spell costs {1} less to cast for each instant and/or sorcery card in your graveyard.
Once each turn, when you cast an instant or sorcery spell, you may create a 4/4 white Angel Cleric creature token with flying and vigilance.

This spell can't be countered.
Haste
Whenever a creature dealt damage by Ripper of the Fang Den this turn dies, put X +1/+1 counters on Ripper, where X is his power.

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.

Concord — When Riptide Mystic enters, if there are four or more card types among permanents you control, you may return target nonland permanent to its owner's hand.

Submerge all creature cards in graveyards. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

Reach
Risen Lumberknot gets +5/+5 as long as you control eight or more lands.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, untap all lands you control. This ability triggers only once each turn.

Target creature you control gets +X/+0 until end of turn. It deals damage equal to its power to up to one target creature.

At the beginning of your upkeep, if an opponent has more life than you, create a 4/4 red Elemental creature token with haste and “Creatures blocking this creature have winnow.” (Damage dealt to a creature with winnow causes its controller to lose that much life.)

Bloodprice {B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Destroy target creature.

Bloodprice {2}{B} (You may cast this card by sacrificing a creature and paying its bloodprice.)
Create X 2/2 black Demon creature tokens, where X is one plus the number of creatures that died this turn.

Destroy all creatures with mana value 3 or less.

Flying
Whenever Rivha and at least two other creatures attack, exile all other attacking creatures you control. For each creature exiled this way, create a 3/3 white Angel creature token with flying that's tapped and attacking.

First strike
Whenever a creature dealt damage by Roadside Reaper this turn dies, you may discard a card. If you do, put a +1/+1 counter on Roadside Reaper and draw a card.

Creatures you control get +2/+0 and gain menace until end of turn. (They can't be blocked except by two or more creatures.)

Whenever Roaring Illusion attacks alone, for each other creature you control, create a token that's a copy of that creature and that's tapped and attacking. Exile those tokens at the beginning of the next end step.

Search your library for up to two basic land cards and put them onto the battlefield tapped, then shuffle.
Fuse (You may cast one or both halves of this card from your hand.)