msem-instigator

{T}: Add {C}.
{T}, Exile two cards from your graveyard: Add {G} or {U}.

Put a +1/+1 counter on each creature you control that entered this turn. (Then exile this card. You may cast the creature later from exile.)

{T}: Add {R} or {W}. You lose 1 life unless you have less life than an opponent.

Target creature gets +2/+2 until end of turn. If it's multicolored, it also gains indestructible until end of turn.

Radiant Vistas enters tapped.
{T}: Add {W} or {U}.
{W}{U}, {T}, Sacrifice Radiant Vistas: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Return target creature card from your graveyard to your hand. Then if this spell was kicked, return another target creature card from your graveyard to your hand.

As long as you control two or more other Pirates, Ragavan has haste.
Whenever one or more Pirates you control deal combat damage to a player, create a tapped Treasure token.

Whenever you cast a noncreature spell, Rageborn Pyromancer gets +1/+1 until end of turn.
{1}{R}: Rageborn Pyromancer gets +1/+0 and gains flying until end of turn.

Target creature gets +2/+0 and gains trample and haste until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Raider's Den enters tapped.
{T}: Add {R}.
{R}, {T}: Target creature you control gains menace until end of turn. Activate only as a sorcery and only if you control a red creature.

({T}: Add {G} or {U}.)
Rainforest Spring enters tapped.

({T}: Add {W} or {U}.)
Rainsculpted Gorge enters tapped.
{1}, {T}: Add {W}{W} or {U}{U}.

Raintouched Basin enters tapped.
{T}: Add {U}.
Desertcycling {1}{U} ({1}{U}, Discard this card: Search your library for a Desert card, reveal it, and put it into your hand, then shuffle.)

{T}: Look at the top card of your library. If its mana value is equal to the number of lands you control, you may reveal it and draw a card.
{1}, Return a land you control to its owner's hand: Scry 1.

Target creature you control gets +2/+2 until end of turn and must be blocked this turn if able.

Rakkiri Initiate gets +0/+2 as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

When Ralezza's Disciple enters, if you control an enchantment, you gain 3 life.

Ralora, Unforgiving Depths enters tapped.
Whenever a source deals damage to you, put a creation counter on Ralora.
{T}, Remove ten creation counters from Ralora and sacrifice it: It deals 10 damage to target player or planeswalker.

Whenever you cast a spell that doesn't share a color with Raloran Adept, you may switch target creature's power and toughness until end of turn.

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

Target creature you control gets +1/+1 and gains hexproof until end of turn.

Enchant opponent
When Ranidaphobia enters, create a 1/1 blue Frog creature token.
Creatures enchanted player controls can't block Frogs.

Choose a Function added to Rapid Recursion. Create a Function token with those effects. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
Draw a card.

Target creature can't be blocked this turn. It explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then you may put that card in your graveyard.)

Menace
When Rattled Bones dies, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)