msem-instigator

Counter target spell if it wasn't cast from a player's hand.

Rakkiri Initiate gets +0/+2 as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

[+1]: The next card you foretell this turn costs {0} to foretell. You may discard a card. If you do, draw a card.
[–3]: Teufel deals 4 damage to any target and you gain 4 life.
[–6]: You get an emblem with “Whenever you cast a spell, you may pay life equal to the amount of mana spent to cast it. If you do, copy that spell and you may choose new targets for the copy.”

Mill five cards, then return up to one permanent card from your graveyard to your hand.

When Lost Empire's Legacy enters, create two Treasure tokens.
{1}, {T}, Sacrifice an artifact: Return target artifact card from your graveyard to your hand.

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.

Whenever you cast an instant or sorcery spell, Clever Infiltrator gets +2/+0 until end of turn and can't be blocked this turn.

Rosesworn Knight gets +1/+1 as long as it's embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

At the beginning of your upkeep, each player sacrifices a nonbasic land.

Whenever a creature you control assaults, put a +1/+1 counter on Devoted Nomad.

When Rousing Battlehound enters, other creatures you control get +1/+1 until end of turn. Other Hounds you control gain first strike until end of turn.

When Lost Kitten leaves the battlefield, create a 1/1 white Peasant creature token.

{1}: Look at the top card of your library.
{G}, {T}, Mill a card: Untap another target creature.

Whenever an embattled creature you control dies, you may return Skhorvall Eternal from your graveyard to your hand. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Fiery Explosion deals 5 damage to target creature or planeswalker.

Draw three cards.
Reprise {5}{U}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

Nonland permanents have “This permanent doesn't untap during your untap step” and “{2}: Untap this permanent.”

{1}{U}: Mercurial Merfolk gets +2/-2 until end of turn.
When Mercurial Merfolk dies, draw a card.

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.)
Whenever Robot Herder deals combat damage to a player, create a 1/1 colorless Servo artifact creature token.

Flying
You may cast black spells with mana value 3 or less by paying life equal to their mana values rather than paying their mana costs.
{B}, Sacrifice another creature: You gain 3 life.

Create two 1/1 red Elemental creature tokens. When you do, target creature you control gets +X/+X and gains trample until end of turn, where X is the number of Elementals you control.

When Lucien's Trail enters, exile target creature or enchantment an opponent controls.
Sacrifice another permanent: Lucien's Trail becomes a copy of the exiled card until end of turn.

{X}{X}, {T}: Draw X cards, then choose X cards in your hand and discard the rest.

Haste
At the beginning of combat on your turn, you may have target artifact or enchantment you control become a creature with base power and toughness X/X, where X is its mana value, in addition to its other types and gain haste until end of turn. (If it's attached to a permanent, it becomes unattached.)

Create a token that's a copy of target creature you control, except it has base power and toughness 2/2.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)