msem-instigator

Sludge-Gill Fox can't be blocked as long as it's attacking alone.
Whenever Sludge-Gill Fox deals combat damage to a player, you may draw a card.

Whenever another creature dies, you gain 1 life.
At the beginning of each end step, if you gained 3 or more life this turn, transform Dowager of Traublassen.

[+1]: Add {R} or {G}.
[–1]: Fatresya deals 2 damage to target creature. That creature can't block this turn.
[–5]: You get an emblem with “Creatures you control get +2/+2 and have haste and trample.”

When Churning Sandwurms enters, remove all counters from target permanent. Put a +1/+1 counter on Churning Sandwurms for each counter removed this way.

Hexproof
At the beginning of your upkeep, put a card from your hand on top of your library. You may shuffle.
{1}: Look at the top three cards of your library, then put them back in any order.
{2}{U}: Draw a card.

Whenever a storied permanent you control enters, tap target creature an opponent controls. (Enchantments and legendary permanents are storied.)

Flash
When Shinrin Spellhunter enters, if an opponent cast a noncreature spell this turn, draw a card.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Sacrifice Bonetooth Darter: Counter target instant, planeswalker, or sorcery spell unless its controller pays {1}.

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)
Lha Elite's power is equal to the number of tokens you control.

Exile all Inscription cards from your graveyard and all exiled Inscription cards you own. For each card exiled this way, you may inscribe it onto a creature you control. (Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost.)

When Poisonblade Herald enters, put a -1/-1 counter on a creature you control.

Whenever Fox of the Mushroom Forest enters or deals combat damage to a player, its activated abilities cost {W} less to activate until your next turn.
{W}, Sacrifice Fox of the Mushroom Forest: Counter target noncreature spell unless its controller pays {2}.

This spell costs {X} less to cast, where X is your devotion to green. (Each {G} in the mana costs of permanents you control counts toward your devotion to green.)
Trample

Enchant creature
Enchanted creature gets +3/+3 and has trample.

Menace
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{R}: Another target creature you control gains menace until end of turn.

This spell costs {1} less to cast for each card you've drawn this turn.
Copy target instant or sorcery spell. You may reselect modes and choose new targets for the copy.

Return up to one target nonland permanent to its owner's hand. If you control a creature with flying, surveil 2.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Deadland Summoner dies, you may put the card it engorged into your hand. If that card is an instant or sorcery card, you may instead cast it without paying its mana cost.

Choose two or four —
• Return target creature to its owner's hand.
• Return target spell to its owner's hand.
• Return target sorcery card from your graveyard to your hand.
• Conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Copy target instant or sorcery spell you control. You may choose new targets for the copy.

Advance {3}{B}{B} (Cast this for {3}{B}{B} to advance it as it enters. {3}{B}{B}: Advance this as a sorcery.)
Whenever Tireless Archivist advances, search your library for a card, put it into your hand, then shuffle.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
{U}{R}: Target creature without prowess gains prowess until end of turn. Activate only if Intelligence is in your graveyard.

Okrophore's power and toughness are each equal to the number of colorless cards in your graveyard.

When Shardsong Seedling enters, conjure two cards named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Haste
Whenever another creature you control dies, each opponent loses 1 life and you gain 1 life.