msem-instigator

Flying

Dekinn, Depths Spirit can't attack or block unless a player has lost 3 or more life this turn.
At the beginning of each player's upkeep, that player may create a Mountain token. If they do, Dekinn deals 3 damage to them.
When Dekinn dies or is put into exile from the battlefield, you may put him into his owner's library third from the top.

Enchant creature
When Delegitimize enters, target opponent sacrifices a land.
Enchanted creature gets +2/+1.

Discard a land card: Target creature can't block this turn.
{R}, Discard a land card: Target creature gets +2/+0 until end of turn.

Up to three target creatures can't block this turn.
Menagerie — If there are five or more creature types among creatures you control, exile the top three cards of your library. You may play one of those cards until the end of your next turn.

Target creature gets +5/+5 until end of turn.
Fabled {4}{G} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

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

Trample
At the beginning of your upkeep, sacrifice another creature. If you do, put X +1/+1 counters on Demented Host, where X is that creature's power.

Destroy target artifact or land.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
When Demolitionist Deviser dies, it deals damage equal to its power to any target.

As Den of Vice enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}, {B}, or {R}.

Denouement deals damage to each creature and each planeswalker equal to the number of enchantments you control.

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.

{4}{B}: Depthlight Beacon gets +1/+1 and gains lifelink until end of turn.
Cycling {2/B} ({2/B}, Discard this card: Draw a card.)

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.)

When Deputy Gibem enters, post a bounty on each creature and each planeswalker. (Put a bounty counter on those permanents. Each of them have “When this permanent dies, each opponent draws a card” as long as it has a bounty counter on it.)

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, target creature can't block this turn.

Frenzy 3 (Whenever this creature attacks and isn't blocked, it gets +3/+0 until end of turn.)
Other red creatures you control have frenzy 2. (If a creature has multiple instances of frenzy, each triggers separately.)
Other creatures you control have frenzy 1.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

({T}: Add {R}.)
Derelict Amphitheatre enters tapped.
{R}, {T}, Reveal a red card from your hand: Scry 1.

{T}: Add one mana of any color.
When you tap Derelict Town for mana, return it to its owner's hand.

Defender
Whenever Derelict Watcher or another Scarecrow you control enters, create a 1/1 black Bird creature token with flying.

Exile the top two cards of your library. Until end of turn, you may play cards exiled this way. If an instant or sorcery spell cast this way would deal damage to a player or planeswalker, it deals double that damage instead.

{2}{G}, Sacrifice Derrivan Beast Tracker: Create a 3/3 green Beast creature token.

When Derrivan Brawnmage enters, target creature gets +3/+3 and gains trample until end of turn.