msem-instigator

Improve {1} ({1}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
At the beginning of combat on your turn, target creature you control with mana value 3 or less can't be blocked this turn. If Streetwise Investigator has two or more counters on it, that creature gains vigilance until end of turn.

Haste
Whenever Malformed Mongrel deals combat damage to a player, discard a card.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Topan Curemaster encourages a creature, you gain 1 life.

Equipped creature gets +2/+0 and has first strike.
Equip Cleric or Knight {1}
Equip {3}

Enchant player
At the beginning of each end step, create X 1/1 green Snake creature tokens, where X is the amount of life enchanted player lost this turn.

Whenever Murkriver Trawler attacks, until end of turn, target Rogue gains “Whenever this creature deals combat damage to a player, draw a card.”

Renown 1
When Marshal Jin Guiying becomes renowned, you may search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.

Encourage ({T}: Another target creature you control gets +1/+1 until end of turn. Encourage only as a sorcery.)
Whenever Leotau Rider encourages a creature, that creature gains trample until end of turn.

Riga's Workshop enters tapped.
When Riga's Workshop enters, you may mill two cards.
{T}: Add {U} or {R}.

Target player puts the bottom X cards of their library into their graveyard.

Flash
When Artisan of Marrow enters, exile another target creature until Artisan of Marrow leaves the battlefield.

Flying, haste
When EHSAE, Entelan Skycraft deals combat damage to a player, you may return it to its owner's hand. If you do, you may search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.
Crew 3

Choose two —
• Put three +1/+1 counters on target creature.
• Target player searches their library for up to two basic land cards, reveals those cards, puts one onto the battlefield tapped and the other into their hand, then shuffles.
• Target creature you control fights target creature you don't control.
• Target player gains 5 life.

Whenever this creature enters or attacks, create a 2/1 white Soldier creature token. Exile up to one target nonland permanent with mana value 3 or less an opponent controls until that token leaves the battlefield.
Other permanents you control have ward {1}.

Whenever Guided Medic attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Lifelink

Rustshell Crustacean gets +1/+1 for each artifact you control.
Whenever Rustshell Crustacean attacks, choose one —
• Search your library for an Equipment card, reveal it, and put it into your hand, then shuffle.
• Create a Treasure token.

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

Whenever a -1/-1 counter is put on a creature you control, you gain 1 life.
{1}{B}, Pay 1 life: Untap target Cleric. You may remove a -1/-1 counter from that creature.

Destroy target nonland permanent. You may return a card that shares a card type with that permanent from your graveyard to your hand.

Once each turn, when you cast an instant or sorcery spell, you may exile the top two cards of your library if you cast it for its showcase cost, otherwise, look at the top two cards of your library, then put one on the bottom of your library and exile the other. You may play cards exiled this way until you exile one or more other cards with For the Court of the Queen.

When Cryptic Sentinel enters, attach any number of target Auras you control to Cryptic Sentinel.
{G}{W}, Sacrifice an Aura: Tap Cryptic Sentinel. It gains indestructible until end of turn.

Creatures can't attack you or planeswalkers you control unless their controller pays {X} for each of those creatures, where X is the number of Wizards you control.

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, you may return target creature card from your graveyard to your hand.
Equip {2}

Whenever a creature you control becomes monstrous, draw a card.

Flying
When Witch of Spring's Promise enters, shuffle any number of cards from your hand into your library, then draw that many cards plus one.