msem-instigator

Each other creature you control that's a Merfolk or an Elemental gets +1/+1.
Whenever you cast an instant, sorcery, or Merfolk spell, you may pay {1}. If you do, create a 1/0 blue Elemental creature token.

Choose one —
• Destroy target artifact.
• You gain 4 life.

Whenever Borsuppa Roughrider attacks, create a colorless Desert land token named Scoured Path with “{T}: Add {R}.” Sacrifice that token at the beginning of the next end step.

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.”

Flying, deathtouch
Whenever an opponent loses life for the first time each turn, that player loses 1 life and you gain 1 life.

{2}, Remove a +1/+1 counter from a creature you control: Draw a card.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
When Ushi Yun enters, create an Idol token.
As long as you're in a renaissance, artifacts you control have “{T}: Draw a card.”

When Ol' Sycamore enters, choose up to two —
• Ol' Sycamore fights another target legendary creature.
• Destroy target noncreature storied permanent. (Enchantments and legendary permanents are storied.)

Ward {2}
{G}{G}{G}, {T}, Exile a creature card from your graveyard: Search your library for up to two creature cards that share a name with the exiled card, reveal them, put them into your hand, then shuffle.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Return to the battlefield up to X target nonland permanent cards from your graveyard that were put there from the battlefield this turn.
5 | If a permanent entering the battlefield causes an ability of a permanent you control to trigger this turn, that ability triggers an additional time.

When Patrol Droid dies, if it attacked this turn, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

When Skelephant enters, you may mill three cards.
Foresight — Whenever you draw your second card each turn, you may put target creature card from your graveyard on top of your library.

Cast this spell only if you control a creature.
Exile all creatures.

Whenever Mawdryk, Endrison Warden or another nontoken Elf creature you control enters, create a 1/1 green Elf Druid creature token.
{B}{G}, Sacrifice two Elves: Destroy target non-Elf creature.

Harmony — Creatures you control gain double strike until end of turn.
When Twirling Duet enters, harmonize. (Trigger up to one harmony of one permanent you control.)

When Ralezza, Weaver of Okthuros enters, you may put target Aura card that could enchant it from a graveyard onto the battlefield attached to Ralezza.
{1}{W}, Sacrifice an Aura: Ralezza gains indestructible until end of turn.

{T}: Add {C}.
{T}, Pay 1 life: Add {B}.
{5}{B}, {T}, Sacrifice Collapsing Ridges: Return target creature card from a graveyard to the battlefield under your control. Activate only as a sorcery.

({T}: Add {U}.)
Aerie's Pillar enters tapped.
Flying
{2}{U}{U}: Aerie's Pillar becomes a creature in addition to its other types until end of turn.

Forlorn Path enters tapped unless you control one or fewer other lands.
{T}: Add {B} or {G}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Exile the top card of your library. You may cast it. (Then exile this card. You may play the land later from exile.)

Draw four cards, then untap up to two target lands.

Whenever Dusk Insurgent perseveres, create a 1/1 white Warrior creature token. (A creature perseveres when it survives damage.)

Ominous Dragoncaller gets +1/+1 and has flying as long as you control a Dragon.

Out-of-Depth Amateur can't attack or block alone.
Attain {4}{R} ({4}{R}: Transform this. Spend at least three colors of mana to activate this, and only as a sorcery.)

Protector of the Gates can't attack unless it's equipped, enchanted, or has a card inscribed onto it.