msem-instigator

As Nebula of Empty Gold enters, choose two or three colors. You lose life equal to the number of colors chosen this way.
{T}: Add one mana of any of the chosen colors.

At the beginning of each end step, if a creature an opponent controlled died this turn, return a creature card from your graveyard to the battlefield.

Equipped creature has all activated abilities of all creature cards in your graveyard.
Equip {3}

Look at the top seven cards of your library. You may reveal an Avatar card and/or an enchantment card from among them and put those cards onto the battlefield. Put the rest on the bottom of your library in any order.

Choose a creature card name. Each player sacrifices a creature, then each player who controls a creature with the chosen name gets a poison counter.
Draw a card.

Flash
Enchant creature
Whenever enchanted creature deals combat damage, put that many +1/+1 counters on it.
When enchanted creature leaves the battlefield, distribute X +1/+1 counters among any number of target creatures you control, where X is the number of +1/+1 counters it had on it.

Whenever Neon Claw Knight enters or attacks, choose one. Create a Function token with that effect. (It's an enchantment. As you cast an instant or sorcery spell, sacrifice any number of Functions to add their effects to that spell.)
• This spell can't be countered.
• This spell costs {R} less to cast.
• If this spell would deal damage to a permanent or player, it deals that much damage plus 1 instead.

Flying, trample
Nether Fiend enters with a lifelink counter on it.
{B}{B}, Pay 6 life, Remove a lifelink counter from Nether Fiend: Draw six cards.

Enchant opponent
Enchanted player plays with the top card of their library revealed.
You may cast the top card of enchanted player's library, and you may spend mana as though it were mana of any type to cast it.

Whenever you conjure a card, if its name isn't noted for Neural Dreams, you may note its name.
Spells you cast with a name noted for Neural Dreams cost one mana of any color less to cast. (If it doesn't have a colored mana symbol in its cost, it costs {1} less.)

Counter target instant or sorcery spell unless its controller pays {3}.

Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.
Reconstruct {X}{G}{G}{G} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)
You can't sacrifice creatures or lands to pay Never Enough's reconstruct cost.

As New Divide enters, you may pay 2 life. If you don't, it enters tapped.
{T}, Sacrifice New Divide: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Whenever a creature you control enters, it gets +2/+1 until end of turn.

{U/B}{U/B}: Return Nherix, the Soulcage from your graveyard to the battlefield tapped.
{6}: Return target creature card with mana value 2 or less from your graveyard to the battlefield tapped.

Draw a card. The next noncreature spell you cast this turn costs {2} less to cast.
Showcase {3}{R} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Target player loses X life and you gain X life, where X is the number of permanents you control with counters on them.

Discard two cards, then draw a card for each card discarded this way. Night of Falling Stars deals damage equal to the total mana value of the discarded cards to each creature.

At the beginning of your upkeep, if there are no noncreature cards in your graveyard, you may return target creature card from your graveyard to the battlefield.

Flying
Whenever an opponent discards a card, put a +1/+1 counter on Nightbane Specter.
Whenever Nightbane Specter deals combat damage to a player, that player discards a card.

Whenever Nightly Herald attacks, it deals damage to the defending player equal to the number of Wolves and Werewolves you control.

Create a token that's a copy of target creature card in your graveyard, except it has no mana cost.

Nightshaper's Domain enters tapped.
{T}: Add {B}.

Whenever a creature attacks one of your opponents, that player loses 1 life.

Once each turn, when another creature dies, you may crystallize. (Put a +1/+1 counter on a creature you control or create a Treasure.)
Whenever an artifact you control dies, Nihilistic Shock Trooper deals 1 damage to each opponent.