msem-instigator

Enchant creature you control
Enchanted creature gets +1/+1.
When enchanted creature dies, return it to the battlefield under your control, then arm it. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Flying, ward {3}
Whenever Sphinx of Myriad Futures attacks, look at the top three cards of your library and reveal one of them. The defending player may have you put the revealed card into your hand. If they don't, put the other two cards into your hand. Then put the remaining cards into your graveyard.

Reach
You may have other creatures you control enter as a copy of any creature card in a graveyard with equal or lesser mana value.

I — Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
II — You may put a land card from your hand onto the battlefield.
III — Lands you control gain “{T}: Add one mana of any color” until end of turn.

{4}{G}{G}, Exile six other cards from your graveyard: Return Trifold Atrocity from your graveyard to the battlefield with three +1/+1 counters on it. Activate only as a sorcery.

Rot-Sand Ruins enters tapped unless you control another Desert.
{T}: Add {B} or {G}.

When Chroma's Guidance enters, create a 2/2 green Wolf creature token.
Whenever you create a creature token, put a +1/+1 counter on it.

Flying
If a triggered ability of another permanent you control would trigger for the first time each turn, that ability triggers an additional time.

When Dregscape Wretch dies, create a 2/2 black Zombie creature token.

When King of Bones enters, exile up to ten target creature cards in graveyards. Each opponent loses X life and you gain X life, where X is the number of cards exiled this way.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever Conchhorn Shinygrabber attacks, you may pay {1}. If you do, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{W}{U}{B}{R}{G}: Conchhorn Shinygrabber gets +3/+3 and gains lifelink until end of turn.

Whenever Lampad of Anathemas or another enchantment you control enters, target creature an opponent controls gets -1/-1 until end of turn.

Abomination Sculptor has deathtouch and lifelink as long as it's attacking.

{1}, {T}, Move a -1/-1 counter from another creature onto Harried Apothecary: Each opponent loses 1 life and you gain that much life.

{1}, {T}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
{2}, {T}, Exile an instant or sorcery card from your graveyard: Stormvolt Apprentice deals 1 damage to each opponent.

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Whenever Stalwart Cathar and at least two other creatures attack, Stalwart Cathar gets +2/+0 until end of turn. Untap it.

When Urn of Heroes enters, you may search your library for a legendary card, put that card into your graveyard, then shuffle.
{T}: Add {C}.

Reach (This creature can block creatures with flying.)
Whenever a land you control enters, Rammanethi Sandshaper deals 1 damage to target creature with flying.

As an additional cost to cast this spell, you may discard a card. If you do, this spell costs {4} less to cast.
Total Process Failure deals 5 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

{T}: Add {C}.
{1}, {T}, Exile Exotic Isle: Search target opponent's library for a land card and put it onto the battlefield tapped under your control, then that player shuffles. Activate only as a sorcery.

{T}: Add {C}.
{4}, {T}, Sacrifice Elgaud Fortress: Create a token that's a copy of target artifact you control. Activate only as a sorcery.

At the beginning of your upkeep, you lose 1 life, then reveal the top card of your library. You lose life equal to its mana value unless it is a creature card. Put that card into your hand.

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

Destroy target enchantment, then create a 1/1 white Soldier creature token.