msem-instigator

When Poisoned Shiv enters, destroy target creature or planeswalker.
Equipped creature gets +2/+0 and has deathtouch.
Equip {2}

Search your library for a land card and put that card onto the battlefield tapped with a venom counter on it. It gains “Whenever this land is tapped for mana, you lose 1 life.” Then shuffle.

Flash
Excess damage Polarity Sage would deal to an attacking creature is dealt to that creature's controller instead.

Untap target creature and upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Flying
• Hexproof

{2}{W}, Sacrifice Pompous Explorer: Destroy target artifact or enchantment.

Inspired — Whenever Pon's Apprentice becomes untapped, target creature you control has base power and toughness 5/5 until end of turn.

Whenever a creature you control leaves the battlefield, you may pay {1}. If you do, scry 1.
{3}{U}, Return a creature you control to its owner's hand: Draw a card.

Create a token that's a copy of target creature you control.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

Counter target spell unless its controller pays {2}.
Wanderlust — If that spell has mana value 2 or less and you control four or more differently named lands, counter that spell.

Whenever Portal Inhibitor attacks, exile target nonland card from defending player's graveyard. Copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)

{1}, {T}: Return target creature you control and each Aura attached to it to their owners' hands. Activate only as a sorcery.

Return Portal to the Unknown to its owner's hand: Add {U}{U}{U}. The next card you cast this turn can be cast as though it had flash.

Whenever a player cycles a card, Possibility Grinder gets +2/+2 until end of turn.

When Possibility Scope enters, search your library for a land card, exile it, then shuffle.
{T}: Target land you control becomes a copy of a land card exiled with Possibility Scope until end of turn.

This spell costs {2} less to cast if an opponent controls a creature with a bounty counter on it.
Postmark Bullet deals 3 damage to any target.

When Postmortem Contemplation enters, draw a card.
{1}{U}: Draw a card, then discard a card.

Scry 2, then draw two cards. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Vigilance, trample
{5}{R}{G}: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)

This spell costs {1} less to cast for each artifact you control.
Choose two —
• Creatures without flying can't block this turn.
• Two target creatures get +2/+0 until end of turn.
• Power Drive deals 3 damage to any target.

Spells cost {3} more to cast this turn.
Activated abilities that aren't mana abilities cost {3} more to activate this turn.

Whenever a creature you control deals combat damage to a player this turn, add that much {R}. Until end of turn, you don't lose this mana as steps and phases end.

{T}: Add one mana of any color. Spend this mana only to cast a multicolored spell.

Whenever Power of Redemption attacks, choose one —
• Remove all -1/-1 counters from all creatures you control.
• Untap all creatures you control.

When Powercell Engineer enters, create a tapped colorless Powercell artifact token with “{T}: Add {C}.”

When Practiced Sorcerer enters, return target noncreature, nonland card from your graveyard to your hand.