msem-instigator

Whenever another artifact you control enters, put a +1/+1 counter on Metalwork Machinist.

Whenever Arena Challenger deals damage to a creature, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• First strike
• Prowess

When Malicious Growth enters and at the beginning of your upkeep, put two +1/+1 counters on target land you control.
{1}{G}: Target land you control becomes a 0/0 Elemental creature with haste and vigilance until end of turn. It's still a land.

Destroy target creature. Then if you control a Wizard, that creature's controller loses 1 life for each creature card in their graveyard.

Flying
When Skystream Mantas is returned to your hand from the battlefield, draw two cards.

Puzzlebox (Begin the game with this and another card you own from outside the game in the command zone, locked. That card is face down until you unlock this.)
{0}: Unlock Tesseract Conjecture. If the revealed card shares a mana value with three or more permanents you control, cast it without paying its mana cost.

Flash
Flying
When Mending Valkyrie enters, choose target permanent you own or permanent card with mana value 3 or less in your graveyard. You may return it to your hand.

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Haste
When Inferno Forerunner enters, you may have target creature gain haste until end of turn.

{2}, {T}: Reveal the bottom card of your library. You gain life equal to its mana value. You may put it into your graveyard.

Each player sacrifices X lands. Chew the Scenery deals X damage to each creature.

Vaporizing Blast deals 3 damage to target creature. If that creature has a permanent attached to it, instead Vaporizing Blast deals 7 damage to that creature and 2 damage to that creature's controller.

Destroy target creature or planeswalker, then exile its controller's graveyard.

Whenever a nontoken creature you control dies, create a white Angel creature token with flying and that creature's name and base power and toughness.

Fire from Above deals 2 damage to target opponent and each creature with flying that player controls.

{R}, {T}: Sandbluff Slinger deals 1 damage to any target.
Quickdraw {1}{R} (When a creature you control blocks or becomes blocked, you may cast this spell for {1}{R}.)

Motley — At the beginning of combat on your turn, if there are five or more names among nonland permanents you control, Ochre Knight gets +2/+1 until end of turn and you gain 1 life.

{T}: Scry 1.
{1}{U}, {T}: Reveal the bottom card of your library. If it's an artifact or enchantment card, put it into your hand.

Gain control of target non-Pirate, non-Rogue creature until end of turn. Untap that creature. It gains haste until end of turn. Pirates and Rogues you control get +1/+0 until end of turn.

At the beginning of combat on your turn, target creature you control has base power and toughness 5/5 until end of turn.

Target creature gets -2/-2 until end of turn. When that creature dies this turn, create a tapped 2/2 black Zombie creature token.

Vigilance
Imisti's Commando can't be blocked by creatures with lesser power.
Whenever Imisti's Commando deals combat damage to a player, draw a card.

Discard your hand, then draw seven cards. When you do, you may cast a card with mana value X or less from your hand without paying its mana cost, where X is the number of card types among cards in your graveyard.

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if two or more land cards are in your graveyard.