Rattling Soundvein enters the battlefield tapped.
When Rattling Soundvein enters the battlefield, you may pay 1 life. If you do, add one mana of any color other than red.
{T}: Add {R}.

Drop — When Rave Mastermind enters the battlefield, target player discards a card. If you didn't cast any creature spells during your last turn, that player discards two cards instead. Put each land card discarded this way onto the battlefield tapped under your control.

When Ravenous Lich enters the battlefield, you may sacrifice another creature. If you do, put two +1/+1 counters on Ravenous Lich.
Escape—{5}{B}{B}, Exile four other cards from your graveyard.

When Razelit Meditation enters the battlefield, create two 1/1 red Soldier creature tokens.
{1}{R}, Sacrifice Razelit Meditation: Razelit Meditation deals 3 damage to target player or planeswalker.

When Reaching Remnant enters the battlefield, it deals 4 damage to target creature with flying you don't control.
Spellcharge 3

When Remnant of Zakros enters the battlefield, choose one —
• Each player sacrifices a creature.
• Each player sacrifices an enchantment.

Vigilance, menace
When Restless Sylph enters the battlefield, if you're ancient and you cast it, untap all lands you control.

Flying
Drop — When Revenant Benefactor enters the battlefield, if you didn't cast any creature spells during your last turn, return target creature card from your graveyard to the battlefield.

When Revenant of Winter enters the battlefield, tap target creature you don't control. It doesn't untap during its controller's next untap step.
Escape—{4}{U}, Exile four other cards from your graveyard.

When Revolutionary Supplier enters the battlefield, you may search your library for a card named Explosive Canister and/or a card named Fencer's Foil, reveal them, put them into your hand, then shuffle.
The first artifact spell you cast each turn costs {1} less to cast.

When Rib Collector enters the battlefield, if it wandered, return target creature card from your graveyard to your hand.
Wander—{1}{B}, Sacrifice another creature.

When Riotous Rockers enters the battlefield, it deals 3 damage to up to one target that was dealt damage this turn.

Reach
When Roaming Treefolk enters the battlefield, target creature or Ruin gets +2/+2 until end of turn.
Wander {5}{G}

When Rose Court Claymore enters the battlefield, you may attach it to target creature you control.
Equipped creature gets +2/+0.
Equip {2}

This spell costs {X} less to cast, where X is the amount of life you have more than your starting life total
Lifelink
When Rose Garden Guardian enters the battlefield, put a +1/+1 counter on each other creature you control with lifelink.

When Rotroot Hauler enters the battlefield, mill three cards, then you may put a permanent card in your graveyard on top of your library.

Flash
When Sanctum of the Two Truths enters the battlefield, draw two cards.
Spellcharge 4

Prowess
When Satyr Arsonist enters the battlefield, destroy target nonbasic land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Flash
When Seal Away enters the battlefield, exile target tapped creature an opponent controls until Seal Away leaves the battlefield.

When Seer of the Aspirants enters the battlefield, surveil 1.
Wander {2}{G}

Trample
When Seismic Chimera enters the battlefield, bless target creature.

When Shaman of Rime's Fury enters the battlefield, create a 0/0 colorless Spirit creature token. Put a number of +1/+1 counters on that token equal to the total number of instant and/or sorcery cards you own in exile and in your graveyard.

Enchant creature you control
When Shatter the Reflection enters the battlefield, you may destroy target artifact or enchantment.
Enchanted creature gets +1/+0 and has deathtouch.

Flash
When Sheltering Melusine enters the battlefield, creatures your opponents control get -X/-0 until end of turn, where X is the number of instant and/or sorcery cards in your graveyard.

When Sinister Sampler enters the battlefield, exile up to one target artifact and up to one target artifact card in a graveyard.
{2}{VP}{U}{B}, {T}: Create a token that's a copy of a card exiled with Sinister Sampler. Activate only as a sorcery.