msem-instigator

Target attacking creature gets +3/+1 and gains trample until end of turn. (Then exile this card. You may cast the creature later from exile.)

Whenever Reclamation Grovesculptor enters or attacks, put a growth counter on target noncreature permanent. It becomes a colorless Forest land and loses all other card types and land types.

Until end of turn, target creature gets +X/+X and can only be blocked by X or more creatures.

Enchant planeswalker
Enchanted planeswalker has “+2: Draw two cards, then put a card from your hand on the bottom of your library.”

Flash
Flying
When Turela, Defiant Angel enters, exile all other creatures you control. Return them to the battlefield under their owner's control at the beginning of the next end step.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Target creature you control can't be blocked by creatures with power 2 or less this turn.
[Lore III] Draw a card.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Target opponent sacrifices a creature or planeswalker.
3 | That player also sacrifices an artifact or enchantment.

Whenever Overgrowth Host attacks, germinate. Then creatures you control that are Saprolings or have counters on them gain trample until end of turn.
Saprolings you control get +1/+1.

Enchant creature
Enchanted creature can't attack or block.

Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Leonin Sandfighter enters, if tribute was paid, it gains first strike. Otherwise it gains double strike. (This effect lasts indefinitely.)

Put three +1/+1 counters on target land. It becomes a 0/0 colorless Elemental creature with haste that's still a land.
Orchestrate—Sacrifice a land. (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

Splintering Hail deals 5 damage divided as you choose among any number of target blocking creatures.

{1}: Danaj Sightseer gains lifelink until end of turn if {W} was spent to activate this ability. The same is true for flying and {U}, menace and {B}, first strike and {R}, and trample and {G}.
At the beginning of your end step, if you've spent {W}{U}{B}{R}{G} to cast spells and/or activate abilities this turn, put three +1/+1 counters on Danaj Sightseer.

Flying
Harrier's Falcon can't attack or block alone.

When Meletis Oracle enters, scry 1, then draw a card.

Flying
Whenever Hellkite Omnivore attacks, you may have it consume. If you do, put a +1/+1 counter on Hellkite Omnivore. When a creature is sacrificed this way, Hellkite Omnivore deals 3 damage to any target. (To consume, sacrifice another creature or exile a creature card from your graveyard.)

Flash
Flying
When Branu enters, return up to one other target creature you control to its owner's hand. If you do, create a token that's a copy of that creature, except it's 1/1.

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Create two tapped Treasure tokens. (Then exile this card. You may cast the creature later from exile.)

When Thought Paradigm enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
Whenever you cast a sorcery spell, target player mills three cards.

Create two 1/1 red Soldier creature tokens with haste.
Creatures you control get +1/+1 until end of turn.

When Elven Guard becomes the target of a spell you control, you may pay {G}. If you do, transform it.

{T}: Add {C}.
{T}, Sacrifice Untethered Spire: Choose target land card in your graveyard that was put there from the battlefield this turn. Return that card to your hand.

Archive 5, archive 5, archive 5 (As this enters, shuffle the top five cards of your main library into a new face up library three times. Sacrifice this after the archived libraries are empty.)
At the beginning of your upkeep, exile the top card of each of your libraries. For each card exiled this way, you may play it without paying its mana cost.

Indestructible
Whenever a creature an opponent controls dies, put five +1/+1 counters on Scion of Death.