Minion's Return

Flash
Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.

Naiad of Hidden Coves

As long as it's not your turn, spells you cast cost {1} less to cast.

Crystacean

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Armor of Shadows

Until end of turn, target creature gets +1/+0 and gains indestructible. (Damage and effects that say "destroy" don't destroy it.)

Fae Flight

Flash
Enchant creature
When Fae Flight enters the battlefield, enchanted creature gains hexproof until end of turn.
Enchanted creature gets +1/+0 and has flying.

Whisper Agent

Flash
When Whisper Agent enters the battlefield, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Slitherwisp

Flash
Whenever you cast another spell that has flash, you draw a card and each opponent loses 1 life.

Soul Enervation

Flash
When Soul Enervation enters the battlefield, target creature gets -4/-4 until end of turn.
Whenever one or more creature cards leave your graveyard, each opponent loses 1 life and you gain 1 life.

Lazotep Plating

Amass Zombies 1. (Put a +1/+1 counter on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)
You and permanents you control gain hexproof until end of turn. (You and they can't be the targets of spells or abilities your opponents control.)

Eaten by Piranhas

Flash
Enchant creature
Enchanted creature loses all abilities and is a black Skeleton creature with base power and toughness 1/1. (It loses all other card types and creature types.)

Cunning Nightbonder

Flash
Spells with flash you cast cost {1} less to cast and can't be countered.

Brinebarrow Intruder

Flash
When Brinebarrow Intruder enters the battlefield, target creature an opponent controls gets -2/-0 until end of turn.

Fungal Fortitude

Flash
Enchant creature
Enchanted creature gets +2/+0.
When enchanted creature dies, return it to the battlefield tapped under its owner's control.

Vexing Gull

Faerie Tauntings

Whenever you cast a spell during an opponent's turn, you may have each opponent lose 1 life.

Eel Umbra

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+1.
Totem armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Bladed Battle-Fan

Flash
When Bladed Battle-Fan enters the battlefield, attach it to target creature you control. That creature gains indestructible until end of turn.
Equipped creature gets +1/+0.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Brineborn Cutthroat

Flash (You may cast this spell any time you could cast an instant.)
Whenever you cast a spell during an opponent's turn, put a +1/+1 counter on Brineborn Cutthroat.

Voidmage Husher

Flash (You may cast this spell any time you could cast an instant.)
When Voidmage Husher enters the battlefield, counter target activated ability. (Mana abilities can't be targeted.)
Whenever you cast a spell, you may return Voidmage Husher to its owner's hand.

Merfolk Trickster

Flash
When Merfolk Trickster enters the battlefield, tap target creature an opponent controls. It loses all abilities until end of turn.

Mystic Subdual

Flash
Enchant creature
Enchanted creature gets -2/-0 and loses all abilities. (Mutating onto the creature won't give it new abilities. It can gain abilities in other ways.)

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment enters the battlefield under your control, each opponent loses 1 life.

Ragged Veins

Flash
Enchant creature
Whenever enchanted creature is dealt damage, its controller loses that much life.

So Tiny

Flash
Enchant creature
Enchanted creature gets -2/-0. It gets -6/-0 instead as long as its controller has seven or more cards in their graveyard.

Illusory Ambusher

Flash (You may cast this spell any time you could cast an instant.)
Whenever Illusory Ambusher is dealt damage, draw that many cards.

Riptide Turtle

Feebleness

Flash
Enchant creature
Enchanted creature gets -2/-1.

Offalsnout

Flash
When Offalsnout leaves the battlefield, exile target card from a graveyard.
Evoke {B} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Tamiyo's Compleation

Flash
Enchant artifact, creature, or planeswalker
When Tamiyo's Compleation enters the battlefield, tap enchanted permanent. If it's an Equipment, unattach it.
Enchanted permanent loses all abilities and doesn't untap during its controller's untap step.

Mutual Destruction

This spell has flash as long as you control a permanent with flash.
As an additional cost to cast this spell, sacrifice a creature.
Destroy target creature.

Portal Mage

Flash
When Portal Mage enters the battlefield during the declare attackers step, you may reselect which player or permanent target attacking creature is attacking. (It can't attack its controller or its controller's planeswalkers.)

Stunning Strike

Flash
Enchant creature
When Stunning Strike enters the battlefield, tap enchanted creature and remove it from combat.
As long as enchanted creature isn't legendary, it doesn't untap during its controller's untap step.

Spontaneous Mutation

Flash
Enchant creature
Enchanted creature gets -X/-0, where X is the number of cards in your graveyard.