msem-instigator

When Dabbling Patron enters, if you cast an instant or sorcery spell this turn, create a 1/1 colorless Elemental creature token.

Whenever you cast an instant or sorcery spell, target creature gets +1/+1 until end of turn.

Instant, sorcery, and Dragon cadence (Whenever you cast an instant, sorcery or Dragon spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
{R}, {T}, Discard a card: Draw a card.

When Emberling dies, it deals 1 damage to any target.

{R}, Sacrifice Firebelly Toad: It deals 3 damage to target player or planeswalker.

When Flame Ascetic enters, you may exile up to one instant card and up to one sorcery card from your graveyard. Put a +1/+1 counter on Flame Ascetic for each card exiled this way.

Goblin Exploration Team gets +1/+0 for each non-Mountain land you control.

Prowess
Whenever High Rollers Croupier attacks, you may put a lore counter on a Saga you control.

{1}{U}, Tap an untapped Noble you control: Hired Blades gets +2/+1 until end of turn and can't be blocked this turn.

Prowess
You may activate inscribe abilities from your graveyard as though they were in your hand.

Whenever Karoa, His Roaring Grace deals combat damage to a player, if he's not equipped, create a colorless Equipment artifact token named Banner attached to him. The token has equip {1} and “Equipped creature gets +1/+1.”

When Keen Redtail enters, 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.”)
When Keen Redtail dies, it deals damage equal to its power to any target.

First strike
{R}, Discard a land card: Put a +1/+1 counter on Lavamancer Adept. It gains menace until end of turn.

Whenever you cast an instant, sorcery, or Wizard spell, Leafdown Sizzlemage gets +1/+0 until end of turn.

Haste
Rapport — Whenever Maghbri Hunter and at least one other creature you control become tapped, Maghbri Hunter gets +2/+1 until end of turn.

Equipment spells you cast cost {1} less to cast.
Equip abilities you activate cost {1} less.

Engage (This creature must be blocked each combat if able.)
{R}: Mettlesome Watchkeeper gets +1/+0 until end of turn.

Dragon spells you cast cost {1} less to cast.
{1}{R}: Until end of turn, Miyoga Dragonsoul becomes a 2/2 red Dragon creature with flying and “{R}: Miyoga Dragonsoul gets +1/+0 until end of turn.” Activate only as a sorcery.

{R}, Sacrifice Nacatl Skirmisher: Destroy target artifact.
Stampede — Whenever Nacatl Skirmisher and a creature with greater power attack, creatures you control get +1/+0 until end of turn.

Whenever you cast a spell, Nightfire Adept gets +3/+0 until end of turn if that spell has the same name as a card in your graveyard.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever you cast an enchantment, instant, or sorcery spell, Noble Barracuda gets +1/+0 until end of turn. Scry 1.

Whenever you attack with one or more Pirates, create that many 1/1 white Bird creature tokens with flying that are tapped and attacking. At end of combat, choose one of those tokens, then exile the rest.

Whenever Professor's Assistant becomes tapped, add {R}. Until end of turn, you don't lose this mana as steps and phases end.

{R}, {T}, Exert Provoker of Mountains: Create an X/X red Elemental creature token, where X is the number of spells you've cast this turn. (An exerted creature won't untap during your next untap step.)
{X}{X}{R}, {T}, Sacrifice Provoker of Mountains: Provoker of Mountains deals X damage to any target.

When Royal Retriever enters or when a creature scavenges it, you may discard a card. If you do, draw a card.
Scavenge {R} ({R}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)