msem-instigator

(Activate each submodule once as a sorcery. When this enters, activate one submodule for free.)
{G}{G}{G}: Seed
Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.
{G}{G}{G}: Soil
Destroy target noncreature permanent.
{G}{G}{G}: Stem
Root Module gains “You may play an additional land on each of your turns.” and “Lands you control are every basic land type in addition to their other types.”

When Rootbound Awakener enters, create a green Aura enchantment token named Vivification attached to target creature or land. The token has enchant creature or land and “Enchanted permanent is a creature with base power and toughness 5/5 in addition to its other types.”

Defender
As long as you control an enchantment, Rooted Cavalier has vigilance and can attack as though it didn't have defender.

{1}{U}, {T}, Discard a card: Reveal the top card of your library. Counter target spell unless its controller pays {X}, where X is the mana value of that card.

Destroy all creatures. Each player creates a tapped colorless land token named Lotus Spring with “{T}: Add one mana of any color.”

{T}, Sacrifice Rootshambler: Untap all basic lands you control.

{1}{G}, {T}, Discard a card: Another target creature you control gets +X/+X until end of turn, where X is 4 minus that creature's power.

When Rootwarper enters, you may sacrifice a land. If you do, search your library for a land card, put that card onto the battlefield tapped, then shuffle.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

At the beginning of each upkeep, choose another permanent with the greatest mana value among permanents. Its controller sacrifices it.

Lifelink, haste
Equip abilities that target Rose of Sunspear cost {X} less to activate, where X is her power.

When Roseblood Hart enters, choose one —
• Destroy target artifact.
• Create a Treasure token.

Instant, sorcery, and enchantment spells you cast cost {1} less to cast.

Prowess
When Rosebud Runner enters, exile the top card of your library. During your next turn, you may play that card from exile.

Rosegill Rover can't be blocked.
Whenever Rosegill Rover attacks, you may discard a card. If you do, draw a card.

Rosesworn Knight gets +1/+1 as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Destroy all nonland permanents with mana value 3 or less.

{6}: Create a 1/1 black Worm creature token.

Create a 1/1 green Saproling creature token for each nonland permanent card in your graveyard.

Rot-Sand Ruins enters tapped unless you control another Desert.
{T}: Add {B} or {G}.

When Rotfeeder Slime dies, you gain 2 life for each creature card in your graveyard.

Rotrider Renegade can't block or be blocked.
{1}{B}: Rotrider Renegade gets +1/+1 until end of turn.
Dash—Reveal a Rogue card from your hand, Pay 2 life (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

{2}{G}: Rotted Kalak gains indestructible until end of turn.
Revive {3}{B} ({3}{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.)

Enchant creature
{X}{B}: Enchanted creature gets +X/+X until end of turn.
When enchanted creature dies, return it to the battlefield under your control.

Enchant creature
When Rotten Retinue enters, return target creature card from your graveyard to your hand.
Enchanted creature gets +2/+2 and has deathtouch.