msem-instigator

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.

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.

Flash
{1}{W}: Return Nimble Explorer to its owner's hand.

At the beginning of combat on your turn, you may attach target Equipment you control to Nina, Master of Arms.
Whenever Nina attacks, the next artifact spell you cast this turn costs {R/W}{R/W} less to cast. (This can reduce the amount of generic mana you pay.)

Flash
When Nixie's Edict enters, tap up to two target creatures.
{2}{W}, Sacrifice Nixie's Edict: Put up to one target creature into its owner's library second from the top. Activate only as a sorcery.

Destroy target monocolored permanent.
Reconstruct {4}{B}{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 only sacrifice permanents that share a color with No Good Deed Goes Unpunished to pay its reconstruct cost.

Put target permanent card with mana value 3 or less from a graveyard onto the battlefield under your control.
Leitmotif (If you cast this spell from your hand, exile it as it resolves. When you next cast a spell that shares a color with this card, you may cast this from exile without paying its mana cost.)

Flying
Whenever Novaheart Dragon enters or attacks, you may take an extra turn after this one. If you do, you lose the game at the beginning of that turn's end step.

Flying
When Novaheart Guardian enters, it deals 4 damage to any target.
Whenever a creature or planeswalker dies, put a +1/+1 counter on Novaheart Guardian.

Flash
Whenever Nsimi's Scrambler deals combat damage to a player, look at that player's hand. You may choose a nonland card from it. If you do, that player reveals the chosen card, puts it on the bottom of their library, then draws a card.

Trample
Whenever you attack with another creature with power 4 or greater, put a +1/+1 counter on OH-14 Diamond.

Menace
When OM-6 Walker dies, OM-6 Walker deals damage to each player equal to twice the number of nonbasic lands that player controls.

Observation Field enters with three charge counters on it.
{2}, {T}, Remove a charge counter from Observation Field: Draw a card and gain 2 life.
{T}, Sacrifice Observation Field: Shuffle any number of target cards from your graveyard into your library.

Flash
Whenever you cast an artifact or enchantment spell, put a +1/+1 counter on Observer of Secret Paths. It can't be blocked this turn.

When Ol' Sycamore enters, choose up to two —
• Ol' Sycamore fights another target legendary creature.
• Destroy target noncreature storied permanent. (Enchantments and legendary permanents are storied.)

Oldgrove Nurturer enters with a +1/+1 counter on it.
{G}, Remove a +1/+1 counter from a creature you control: Create a 1/1 colorless Construct artifact creature token.

Trample, haste
Whenever an opponent casts a noncreature spell, you may return Olten Sandwurm to its owner's hand.

Flash
Flying

When Olten Surveyor enters, choose any number. Each opponent creates a 1/1 colorless Servo artifact creature token for each mode chosen.
• Destroy target artifact or enchantment with mana value 3 or less.
• Shuffle up to four cards from target player's graveyard into their library.
• You gain 4 life.

Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)
Creatures with power less than Olten Survivalist's power can't block creatures you control.

Trample
Ward {3} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Flash
When Olten Vipermoa enters, you may return another creature you control to its owner's hand. If you do, put two +1/+1 counters on Olten Vipermoa.

At the beginning of your upkeep, create four 1/1 blue Elemental creature tokens with flying. You gain 4 life.
{2}{W}, Discard Olten's Farewell: Create two 1/1 blue Elemental creature tokens with flying. You gain 2 life.

{T}: Add {C}.
{6}, {T}, Discard a card: Search your library for a multicolored card, exile it, then shuffle. If its mana value is 3 or less, you may cast it without paying its mana cost. If you don't, put it into your hand. Activate only as a sorcery.