msem-instigator

Players can't gain life.
Whenever a player casts a spell, Rage of the Ravaged deals 1 damage to that player.

Haste
Whenever a player casts a spell, Rakkiri Dissident deals 1 damage to that player.

({T}: Add {R} or {G}.)
Whenever Rampant Summit becomes tapped, you lose 1 life unless you control two or more basic lands.

First strike
When Rapacious Rattler enters the battlefield, choose one or two targets you don't control. It deals 2 damage to the first and 1 damage to the second.

Draw two cards. You may play an additional land this turn.
Coalesce {5}{G}{U} (You may cast this from your graveyard for {5}{G}{U}. If you do, put it onto the battlefield as a Horror creature after it resolves. Exile it if it would leave the battlefield.)

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
Flashback {3}{U}

Choose one —
• Destroy target monocolored creature.
• Ria-Demian Charm deals 2 damage to each creature.
• Each player discards two cards and loses 2 life.

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.)

Roggar's Frenzy deals 3 damage to any target.
{2}{R}, Exile Roggar's Frenzy from your graveyard: Create two tapped 1/1 red Elemental creature tokens.

Roggar's Gambit deals 2 damage to any target.
Reprise {1}{R} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)
Damage dealt by sources reprising Roggar's Gambit can't be prevented.

Destroy all nonland permanents with mana value 3 or less.

({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.

Menace
When Ruin Delver attacks, you may sacrifice a land or exile a land card from your graveyard. If you do, you draw a card and you lose 1 life.

{G}: Exile target card from a graveyard. If it was a land card, put a +1/+1 counter on Sacrificial Bull.
{G}, Sacrifice Sacrificial Bull: You gain life equal to its power.

Scorch deals 3 damage to any target.

Choose target card in a graveyard other than a basic land card. Search its owner's graveyard, hand, and library for any number of cards with the same name as that card and exile them. Then that player shuffles.
Scry 1.

When Sealed Riftway enters the battlefield, exile up to one target card from a graveyard.
{2}, {T}, Sacrifice Sealed Riftway: Exile target player's graveyard. Draw a card.

({T}: Add {W} or {U}.)
Whenever Sedate Tundra becomes tapped, you lose 1 life unless you control two or more basic lands.

Reveal the top three cards of your library. Put one into your hand and the rest on the bottom of your library in any order.

Concord — This spell costs {4} less to cast if there are four or more card types among permanents you control.
Vigilance, trample, lifelink, haste

Create a 1/1 colorless Construct artifact creature token. If you control an artifact, create two of those tokens instead.

As long as it's your turn, Seto San is a 3/3 Human Warrior creature with indestructible.
[+1]: Up to one target creature you control gains lifelink until end of turn.
[0]: Create a 1/1 white Warrior creature token.
[–X]: Search your library for an Aura or Equipment card with mana value X and put it onto the battlefield, then shuffle.

Kicker {1}{R} (You may pay an additional {1}{R} as you cast this spell.)
Shal'Draen's Rage deals 1 damage to each creature. If this spell was kicked, it deals 3 damage to each creature instead.

As Shardstone Rift enters the battlefield, you may pay 2 life. If you don't, Shardstone Rift enters the battlefield tapped.
{T}, Sacrifice Shardstone Rift: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

{T}: Add {C}.
{T}, Sacrifice Shifting Canyon: Choose a basic land type other than Plains. Create a colorless land token that's a Plains and the chosen basic land type. Activate only during your upkeep.