msem-instigator

At the beginning of combat on each of your turns, you may sacrifice a land or exile a land card from your graveyard. If you do, create two 1/1 red Goblin creature tokens with haste. Exile those tokens at the beginning of the next end step.

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Legendary creatures you control have hexproof.

Pay 3 life: Put a +1/+1 counter on target creature.

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.”

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.

Once each turn, when Rova, the Fleshweaver enters or you attack with one or more Horrors, you may put a +1/+1 counter on each creature you control. Then if Rova isn't a token, untap each land you control. Until your next turn, you may cast permanent spells as though they had flash.
{2}{G}{G}, Discard Rova: Create a token that's a copy of Rova, the Fleshweaver, except it's 4/4 and isn't legendary. Activate only as a sorcery.

[+1]: Tap target permanent. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
[0]: Put target artifact, instant, or sorcery card from your graveyard on top of your library. If you have an insight counter, you may return that card to your hand instead.
[0]: You get an insight counter.
[–1]: Target creature can't be blocked this turn. Until end of turn, whenever that creature deals damage to an opponent, you draw a card.

When Rubble Seer enters, you may sacrifice a land or exile a land card from your graveyard. If you do, exile the top card of your library. Until the end of your next turn, you may play that card.

({T}: Add {R}, {G}, or {W}.)
Rugged Dominion enters tapped.

Menace
Whenever 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.

At the beginning of your end step, Run & Gun deals damage to each opponent equal to the number of tapped creatures you control.

You may spend mana as though it were mana of any color to cast spells with mana value 5 or greater or to activate abilities of permanents or permanent cards with mana value 5 or greater.
{T}: Add {C}.

Flying
When Rushwater Hunter enters, you may return target creature to its owner's hand.

Improve {1}{U} ({1}{U}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of your end step, if one or more embattled creatures you controlled dealt damage to a player, you may draw a card. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Haste
Whenever an embattled creature you control deals combat damage to a player, you may pay {2}{G}. If you do, create a token that's a copy of that creature, except the token isn't legendary if the creature is legendary. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

When Ryleth, Vengeful Shadow enters, create two 1/1 green Elf creature tokens.
Whenever you attack, you may pay {1}{B/G}. When you do, return target creature card with mana value less than or equal to the number of attacking creature tokens you control from your graveyard to the battlefield tapped and attacking.

Flying
Legendary spells you cast cost {1} less to cast.
{W}{U}{B}{R}{G}: Search your library or graveyard for a legendary card, reveal that card, and put it into your hand. If you searched your library this way, shuffle.

Create a token that's a copy of a creature token you control.
Draw a card.

Sacred Summits enters tapped.
{T}: Add one mana of any color among the color identity of legendary creatures and planeswalkers you control or legendary cards in your command zone.

When Saddled Scuttleback enters, you may search your library for a Crab, Fish, Jellyfish, Kraken, Leviathan, Merfolk, Nautilus, Octopus, Otter, Oyster, Pirate, Seal, Serpent, Shark, Shrimp, Sponge, Squid, Starfish, Trilobite, Turtle, Whale, or Island card, reveal it, put it into your hand, then shuffle.

Trample
When Saddlesaur Guide enters, create a green Aura enchantment token named Hefty Load attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2 and has trample.”

{T}: You gain 1 life.
{1}{W}, {T}: Tap or untap another target creature.

Flying, prowess
Once each turn, when you cast a noncreature spell, you may create a 4/4 blue Sphinx Wizard creature token with flying, then scry 1.
{2}{U}{U}, Discard Sage of the Hereafter: Create a 4/4 blue Sphinx Wizard creature token with flying, then scry 1. Activate only as a sorcery.

Sage's Ashes enters tapped.
{T}, Sacrifice Sage's Ashes: Put target card from a graveyard on top of its owner's library.
{3}, Exile Sage's Ashes from your graveyard: Draw a card.