msem-instigator

Prevent all combat damage that would be dealt this turn.

Flying
Whenever you attack, create two 1/1 white Human creature tokens that are tapped and attacking. Creatures you control get +1/+1 until end of turn.
Fleeting {2}{W}{W} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Play with the top card of your library revealed.
Whenever you draw a card, destroy each creature with the same mana value as that card.

Spiny Ridge enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may put that card into your graveyard.)
{T}: Add {R}.
{4}{R}: Spiny Ridge becomes a Lizard creature. (This effect lasts indefinitely.)

When Reprising Bard enters, exile target instant or sorcery card with mana value 3 or less from your graveyard. When Reprising Bard is no longer on the battlefield, copy the exiled card. You may cast the copy without paying its mana cost.

Reinbreaker Behemoth attacks each combat if able.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Bounty Crusher has trample as long as it's being blocked by a marked creature.

Enchant artifact or creature
Enchanted permanent can't attack and its activated abilities can't be activated.

{T}: Add {U} or {R}.
{U}{R}, {T}: Target creature gains flying until end of turn.

Return target creature you own to your hand.
Scry 1.

You may change any targets of target spell that targets you or a permanent you control. If you don't, counter that spell.

Vanishing 3
Whenever a time counter is removed from Prayers of Defiance, return target creature card from your graveyard to your hand.

Flash
Enchant creature
Enchanted creature gets +1/+1 and has first strike.

Dictate of Rallios deals damage to any target equal to the number of Warriors you control.
Warriorcycling {2}{R} ({2}{R}, Discard this card: Search your library for a Warrior card, reveal it, and put it into your hand, then shuffle.)

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
Remove a +1/+1 counter from Spellsword Elite: The next noncreature spell you cast this turn costs {1} less to cast.

Torch Reveler gets +2/+0 as long as you control an artifact.

(Transform this if it's not attached to a creature. Pay {3}{G} as a sorcery to unattach it.)
Enchant creature you control
Elven Mount's rider gets +3/+3 and has trample.

When Smoldering Husk dies, it deals 2 damage to any target.
{2}{R}: Smoldering Husk gets +2/+0 until end of turn.

When Churning Spellroot enters, create three 1/1 black Worm creature tokens.

Wither (This deals damage to creatures in the form of -1/-1 counters.)

At the beginning of your upkeep, you gain 1 life. Then each opponent may give themselves a poison counter. For each opponent who doesn't, create a 2/2 white Angel creature token with flying.

(Choose only one work as a sorcery to add its ability.)
When Seto's Private Collection enters, creatures you control get +2/+1 until end of turn.
{1}{R}: Bloodline
Attacking creatures you control have first strike.
{2}{W}: Hope's Savior
Attacking creatures you control have lifelink.

{2}, Sacrifice Wicked Fossil: Target player loses 2 life and you gain 2 life.
{2}{B}{B}: Return Wicked Fossil from your graveyard to the battlefield transformed. Activate only during your turn.

Cards in your hand have lifecycle {3}.
{2}{G}, Sacrifice four creatures: Create two tapped 4/4 green Chimera creature tokens.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

Vigilance
When Skaab Grappler enters, you may exile two creature cards from your graveyard. When you do, return another target creature to its owner's hand.