msem-instigator

Harness (You may tap a creature you control as you cast this spell. If you do, reduce this spell's mana cost by that creature's power.)
Magnitude deals X damage to each player and each creature without flying that didn't harness it.

Whenever two or more creatures an opponent controls block, adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)
Enchanted creatures you control have menace.

Each player sacrifices a creature and discards a card.
Fuse (You may cast one or both halves of this card from your hand.)

Creatures your opponents control get -1/-0 until end of turn for each different creature type among creatures you control.

Whenever you cast a spell that doesn't share a color with Pond Tenders, you may put target card from your graveyard on the bottom of your library.

When you're dealt damage, sacrifice Paracosm.
{T}: Add one mana of any color.

When Warrior's Perspective enters, invigorate 1. (Choose a creature with the least power among creatures you control and put a +1/+1 counter on it.)
Whenever a creature you control with a +1/+1 counter on it becomes tapped, you may draw a card. If you do, discard a card.

{T}: Add {G}.
Concord — {T}: Add two mana in any combination of colors. Activate only if there are four or more card types among permanents you control.

Shuffle up to five target cards from your graveyard into your library. Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

As Theodore Harper, Head Librarian enters, choose Fact or Fiction.
• Fact — Permanent spells you cast cost {1} less to cast. This effect can't reduce the amount of mana a spell costs to cast to less than one mana.
• Fiction — When Theodore Harper enters, return a permanent card from your graveyard to your hand.

Lifelink
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

When Wilting Waif dies, each opponent discards a card at random and you scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

Enchant opponent
Creatures enchanted player controls get -2/-2.
Whenever enchanted player casts a noncreature spell, they lose 2 life and you gain 2 life.

Haste
Fleeting {B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Deathtouch
Inspired — Whenever Scar Tattooist becomes untapped, you may have target creature get -1/-1 until end of turn.

When Dregscape Wretch dies, create a 2/2 black Zombie creature token.

Whenever you cast a spell, put a burst counter on Ascending Downfall, then if that spell's mana value is less than the number of burst counters on Ascending Downfall, sacrifice it and it deals damage equal to the number of burst counters on it to any target.

Legendary creatures you control have hexproof.

Vigilance
When Coralight Sentinel enters, create a white Aura enchantment token named Crab's Resolve attached to target creature. The token has enchant creature and “Enchanted creature gets +0/+2.”

First strike (This creature deals combat damage before creatures without first strike.)
When Attended Knight enters, create a 1/1 white Soldier creature token.

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Flying, lifelink

Thunder Wave deals 3 damage to target creature or planeswalker.

When Yamisaran Bladedancer enters, you may attach an Equipment you control to target creature you control.

Fang Den Bouncer can't be blocked by creatures with power 2 or less.