msem-instigator

As Imperial Barracks enters, you may reveal a Mountain or Plains card from your hand. If you don't, Imperial Barracks enters tapped.
{T}: Add {R} or {W}.

Target player draws two cards and loses 2 life.

Each other creature you control that's a Cleric or a Reflection gets +1/+1.
Protective Memory gets +3/+3 as long as you've gained life this turn.

Enchant opponent
When Down with the Ship enters, enchanted player discards a card unless they sacrifice a creature.
{1}{B}, Sacrifice Down with the Ship: Return target creature card from your graveyard to your hand.

Destroy target creature or planeswalker.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Gain control of target creature until end of turn. Untap that creature. It gets +1/-1 and gains haste until end of turn.

Flying, deathtouch
Creatures that aren't Spirits or Warlocks get -1/-1.

When Conscious Taboo enters, look at target opponent's hand. You may exile a noncreature, nonland card from it. For as long as that card remains exiled, its owner may play it. A spell cast this way costs {2} more to cast.

When Journey through Uwaito enters, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name dies, each opponent discards a card.

Arcane Oasis enters tapped unless you control another Desert.
{T}: Add {U} or {R}.

Menace

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.

Wildcast — When Ivier, Soul of the Woods enters, return target monocolored creature card from your graveyard to your hand. If mana from a nonland source was spent to cast Ivier, return that card to the battlefield instead.

When this creature enters, put two -1/-1 counters on a creature you control.
When you put one or more -1/-1 counters on one or more creatures, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Flying
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Crater Burst deals 3 damage to any target. Add {W}{U}{B}{R}{G}. Until end of turn, you don't lose this mana as steps and phases end.

I, II — Create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
Discovery — {2}, Sacrifice an artifact: Draw a card.

{2}{U}{B}: Return Depth Charger to its owner's hand. If you do, return target creature to its owner's hand. That player discards a card.

When Shield of the Unwavering enters, attach it to target creature you control.
Equipped creature gets +2/+2 and has vigilance.
Equip {3}

If an enchanted permanent you control would leave the battlefield, instead destroy one of the Auras attached to it, then that permanent phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Search your library for a creature card with haste, one with reach, one with trample, and one with vigilance, each with different names and reveal them. An opponent chooses two of those cards. Put the chosen cards into your graveyard and the rest into your hand. Then shuffle.

The next creature spell you cast this turn can be cast as though it had flash. When that creature enters this turn, it gains lifelink until end of turn.

Noxious Garden enters tapped.
As Noxious Garden enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Whenever you cast a noncreature spell, upgrade Embodied Soul. (Give it one of the listed counters it doesn't already have.)
• Flying
• First strike
• Vigilance
• Lifelink
{W}: Until end of turn, if Embodied Soul isn't a creature, it becomes a 0/0 Spirit Avatar enchantment creature with “This creature gets +1/+1 for each different kind of counter on it.”