msem-instigator

When Debaser of Truth enters, if you control three or more Horrors, each opponent discards two cards.
Other Horror creatures you control get +1/+1.

When Debt Dignitary enters, tap target nonland permanent. That permanent doesn't untap during its controller's untap step for as long as you control Debt Dignitary.

{T}: Put a flood counter on Decanter of Endless Rivers. Add {U} for each flood counter on it.

Decay deals damage to creatures in the form of -1/-1 counters.
{B}{G}: Until end of turn, target creature deals damage to creatures in the form of -1/-1 counters. Activate only if Decay is in your graveyard.

Whenever Deceitful Soul becomes blocked by one or more creatures, it gets +2/+0 until end of turn.

Primal {B}{B} (During your turn, you may cast this spell for {B}{B} instead of playing a land.)
Search your library for a card and put that card into your hand, then shuffle. Exile Deceitful Tutor.

Deception can't be blocked.
{1}{U}{B}: Target creature can't be blocked this turn. Activate only if Deception is in your graveyard.

If an opponent controls more lands than you, search your library for a Plains card. If an opponent controls more creatures than you, search your library for a creature card with mana value 2 or less. Reveal those cards, put them into your hand, then shuffle.

Target creature gets +2/+2 until end of turn. You may remove a -1/-1 counter from it.

Target opponent discards a card. If a creature card was discarded this way, that player loses 3 life. If a land card was discarded this way, add {B}{B}. If a noncreature, nonland card was discarded this way, draw a card.

Flash
When Decisive Arcanist enters, you may cast target modal instant or sorcery card in your graveyard. Exile that card instead of putting it into your graveyard as it resolves.

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

Whenever another creature you control enters, you may change Declan, Wayward Squire's base power and toughness to that creature's power and toughness until end of turn.

Indestructible (Damage and effects that say “destroy” don't destroy this creature.)
Whenever Declare, the Mother Bear deals combat damage to a player, put a +1/+1 counter on it.

Menace (This creature can't be blocked except by two or more creatures.)

Counter target creature spell, planeswalker spell, or activated ability.

When Decrepit Hero dies, create a 2/2 black Soldier creature token.
Fleeting {1}{B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Haste
When Dedicated Bushwacker enters, other creatures you control get +1/+0 and gain haste until end of turn.

{T}: Add {G}. If a -1/-1 counter was put on a creature you control this turn, add {G}{G} instead.

Target creature gets +1/+0 and gains first strike until end of turn.
Target creature blocks this turn if able.

When Dedicated Waypoint enters, create a 1/1 white Scout creature token.
{T}: Add {R}, {W}, or {B}.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a player activates an ability of an artifact, creature, or land, if it isn't a mana ability, Dedicated Weaponsmith deals 2 damage to that player.

Draw a card. Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Counter target spell with mana value 3 or less. If a spell is countered this way, return it to its owner's hand instead of putting it anywhere else.

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
At the beginning of the upkeep of enchanted creature's controller, that player mills a card.