msem-instigator

Creatures you control get +2/+2 and gain vigilance and trample until end of turn.

{T}, Sacrifice Decrepit Crags: Search your library for a Swamp or Mountain card and put it onto the battlefield tapped, then shuffle.

Exile target creature. Return that card to its owner's hand at the beginning of its owner's next end step.

Flash
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.)

{B}{G}, {T}: Reveal the bottom card of your library and exile it. Target creature gets +X/-X until end of turn, where X is that card's mana value.

Haste
{R}, Sacrifice Deepstone Operative: Destroy target artifact.

Damage dealt by Deepwater Stinger can't be prevented.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. Create a 1/1 green Elf creature token.

As an additional cost to cast this spell, discard a nonland card.
Target player reveals their hand. You choose a nonland card from it. That player discards that card.

Deft Goldsnatch can't be blocked.

Whenever you scry, tap target creature an opponent controls.
{2}{W}{U}: Scry 1. You gain 1 life.

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Each creature you control with a counter on it has ward {2}. (If a creature has multiple instances of ward, each triggers separately.)

Creatures you don't control get -1/-0 as long as their controller is cursed.

Delusional Noble enters with a -1/-1 counter on it.

Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
You may sacrifice any number of artifacts. If you do, draw that many cards.

At the beginning of each player's end step, that player sacrifices a permanent.

Whenever an opponent casts a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Spells your opponents cast cost an additional 2 life to cast until your next turn.

{1}{B}, Sacrifice another creature: Draw a card and create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
{2}{B}, Sacrifice three Idols: Return Demon of Hubris from your graveyard to the battlefield. Activate only as a sorcery.

Create a 4/4 black Demon creature token with flying. You lose 3 life for each Demon you control.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)

When Demonqueller Mage enters, gain control of target creature with power 2 or less until Demonqueller Mage leaves the battlefield.

Flying
When Depraved Imp enters, if you control a legendary creature, put two +1/+1 counters on Depraved Imp.

Whenever you draw your second card each turn, create a 1/1 blue Tentacle creature token.
{3}{G}, Sacrifice two creatures: You gain 1 life and draw a card. Activate only during your turn.

Menace
Other artifact creatures you control have menace.
{2}{B}{R}: Salvage an artifact or creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Trample
When Depthlight Frontliner enters, you may salvage up to one instant card and up to one sorcery card. (Exile those cards from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Hexproof
Rapport — Whenever Depths Stalker and at least one other creature you control become tapped, Depths Stalker gets +1/+0 until end of turn and can't be blocked this turn.