msem-instigator

This spell costs {1} less to cast for each artifact you control.
Gain control of target creature until end of turn. Untap that creature. It gains menace and haste until end of turn.

Target creature gets +1/+2 and gains flying until end of turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U} (You may cast this from the battlefield for its wander cost.)

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Exile each player's graveyard. Create a token that's a copy of a creature card exiled this way.
II — Create a token that's a copy of an artifact or enchantment card exiled with Around the Plane in Three Days.
III — Create a token that's a copy of a land or planeswalker card exiled with Around the Plane in Three Days.

Once each turn, when Atal, the Shroudmaker enters or you attack with one or more Horrors, you may create two tapped 1/1 colorless Human creature tokens. If Atal isn't a token, creatures you control gain flying until end of turn.
{2}{W}{W}, Discard Atal: Create a token that's a copy of Atal, the Shroudmaker, except it's 4/4 and isn't legendary. Activate only as a sorcery.

When All-Blossom Memorial enters, scry 1.
Prismatic — Whenever you cast a multicolored spell, you gain 1 life.
{T}: Add one mana of any color.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
As you choose targets for an instant or sorcery spell, choose up to one additional target.
At the beginning of combat on your turn, gain control of another target creature until end of turn. Untap that creature. It gains haste until end of turn.

Double strike, vigilance, lifelink

Whenever a land you control enters, create a 1/1 red Elemental creature token. Then if you control three or more Elementals, exile Aleryn, Trapseeker, then return him to the battlefield transformed under his owner's control.

[+1]: Create a green enchantment token named Swarm with “At the beginning of your end step, create a 1/1 green Insect creature token.”
[–2]: Create a green enchantment token named Survive with “Whenever a creature you control dies, you gain life equal to its power.”
[–4]: Create a green enchantment token named Scrounge with “Whenever a creature you control enters, draw a card.”

Reach (This creature can block creatures with flying.)

Enchant creature
Enchanted creature gets +2/+2.
Whenever enchanted creature attacks, if it's a Scout, scry 2.

Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.
Metamorph {2}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

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

Whenever another creature you control dies, creatures you control get +1/+0 until end of turn.
Whenever this creature attacks, you may pay {2}{R} and sacrifice another creature. If you do, this creature gains menace until end of turn.

Double strike

Equipped creature has “{2}, {T}: This creature deals 1 damage to any target.”
{4}: Untap equipped creature.
Equip {3}

Glorious end — When Seeker of Conto Sika dies, if it was tapped, draw a card.

Enchant creature
When Vampiric Rise enters, fateseal 2. (Look at the top two cards of an opponent's library, then put any number on the bottom and the rest on top in any order.)
Enchanted creature gets +1/+0 and has flying.

Choose one —
• Qi-Long Gust deals 3 damage to any target.
• You and permanents you control gain hexproof until end of turn.

Choose one —
• Target creature gets +1/+1 until end of turn for each creature you control.
• Creatures you control get +1/+1 until end of turn.

You may have Surging Wurm assign its combat damage as though it weren't blocked.
Surging Wurm gets +2/+2 as long as seven or more cards are in your graveyard.

Destroy target artifact or land.
Kindle 2—{R}, Sacrifice an artifact or land. ({R}, Sacrifice an artifact or land, Exile this card from your graveyard: Create two 1/1 colorless Elemental creature tokens. Kindle only as a sorcery.)

{T}: Add {C}.
{5}, {T}, Sacrifice Ascendant's Cell: You may activate loyalty abilities of planeswalkers you control twice this turn rather than only once.

Menace (This creature can't be blocked except by two or more creatures.)
Infiltrate (Whenever one or more attacking creatures you control aren't blocked, this creature gets +1/+1 until end of turn.)