msem-instigator

{3}: Put a +1/+1 counter on Tinkerer's Assistant.

Equipped creature gets +X/+X, where X is the number of cards in your graveyard.
Sacrifice a creature other than equipped creature: Equipped creature gains lifelink and indestructible until end of turn.
Equip {3}

Whenever Witchfinder Artur enters or attacks, each opponent mills two cards and loses 2 life.
Whenever you cast an instant or sorcery spell, you may exile target instant or sorcery card with mana value less than that spell's mana value from an opponent's graveyard. If you do, cast a copy of the exiled card without paying its mana cost.

Destroy target creature, enchantment, or planeswalker. Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Whenever one or more artifacts you control enter, put a +1/+1 counter on Octopus Shiny-Grabber and you gain 1 life.

Rakkiri Piker has double strike 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.)

Elfcycling {2}{G} ({2}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)

When Unmasker of Fate's Design enters, look at target player's hand. Choose a nonland card from it and exile that card with a puzzle counter on it. As long as that card has a puzzle counter on it, that player may pay {2} and 1 life at any time. If they do, return the exiled card to their hand.

Haunted Estate enters tapped unless another player controls a land that could produce {W} or {B}.
{T}: Add {W} or {B}.

Escalate {2} (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Counter target spell.
• Destroy target creature.
• Discard your hand, then draw two cards.

Menace
When this creature enters, put a -1/-1 counter on a creature you control.

Generative Edge enters tapped.
{T}: Add {G} or {U}.
{G}{U}, {T}, Sacrifice Generative Edge: Conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Trample
When this creature enters, it seeks secrets or valor. (Give it that Oath Aura. Fulfill secrets by attacking with it and two or more other creatures to draw a card. Fulfill valor by dealing combat damage to a player to create a 2/1 white Soldier token.)

You may return a land you control to its owner's hand rather than pay this spell's mana cost.
Marinton-Ravengulch Line enters tapped.
{T}: Add {B}.

Flying, vigilance

Planar Alignment enters tapped.
{T}: Add {C}.
{6}, {T}, Exile Planar Alignment: Search your library for a card, put it into your hand, then shuffle.

({T}: Add {W} or {U}.)
Pool of Light enters tapped unless you control a basic Plains or a basic Island.

Exchange control of two target permanents that share a permanent type.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

Tribute 4 (As this creature enters, an opponent of your choice may put four +1/+1 counters on it.)
When Slaughter enters, if tribute was paid, destroy all other creatures. Otherwise, destroy all creatures you don't control.

This spell costs {3} less to cast if it targets a creature you control.
Exile target creature, then you may return it to the battlefield under its owner's control. Otherwise, put it on top of its owner's library.

Flying
Whenever Flying Scorpion attacks, it gets +1/+0 until end of turn for each creature you control that's not attacking.

Enchant creature
Enchanted creature has deathtouch and menace.
{G}{U}: Enchanted creature gains hexproof and indestructible until end of turn. Tap it.
{R}: Enchanted creature gets +1/+0 until end of turn.

Scry 2, then draw a card. (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.)
Foresee — As you draw Read the Clouds, you may reveal it and pay {1}{U}. When you do, scry 2, then draw a card.

Whenever Merfolk Vandal deals combat damage to a player, you may pay {U}. If you do, transform it.