msem-instigator

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a +1/+1 counter is put on Sejiri Skyhunter, it gains flying until end of turn.

Whenever you cast a noncreature spell, put a number of charge counters on Selection at Danaj equal to that spell's mana value.
At the beginning of your end step, you may remove four charge counters from Selection at Danaj. If you do, look at the top four cards of your library, put one into your hand and the rest on the bottom of your library in a random order.

Create a 1/1 colorless Construct artifact creature token. If you control an artifact, create two of those tokens instead.

Enchant creature
Enchanted creature gets +1/+1 and has lifelink.

Menace
When Selfserving Ghul enters, remove two counters from target permanent.

{3}: Sellsword Contraption becomes the creature type of your choice until end of turn.

Senaturian Legion gets +1/+1 for each other creature on the battlefield named Senaturian Legion.
A deck can have any number of cards named Senaturian Legion.

Return target non-Horror creature to its owner's hand. Scry 1.

Return up to one target creature you control and up to one target creature you don't control to their owners' hands.

When Sending Stones enters, harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)
If you would harmonize, you may trigger a harmony of a permanent card in your graveyard instead.

Choose one —
• Target permanent gains protection from instants and sorceries until end of turn.
• You gain 3 life.
• Draw a card.

Destroy target creature. Trigger a death knell of a permanent you control.

You may put cards with Adventures that permanents you control explore into your hand as though they were lands. (You won't get the counter if you do.)
At the beginning of each end step, if you cast an Adventure spell or a permanent you controlled explored this turn, create a 1/1 green Scout creature token.

Target player discards two cards. If a creature you control died this turn, that player loses 2 life.

{2/U}, {T}: Target creature gets -4/-0 until end of turn.

Choose one —
• Untap each creature you control.
• Harmonize twice. (To harmonize, trigger up to one harmony of a permanent you control.)

When Sentient Contraption enters, create a 1/1 colorless Thopter artifact creature token with flying.

Target noncreature artifact you control becomes a 0/0 artifact creature. Put three +1/+1 counters on it.

Lionize {1}{W} ({1}{W}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Flying

Reach, ward {3}

Soldiercycling {1}{W}, Wizardcycling {1}{U}, Zombiecycling {1}{B}, Warriorcycling {1}{R}, Elfcycling {1}{G} ({1}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)
Sentinel of Latter Days is every creature type as long as it's in your library.

Equipped creature has vigilance and reach.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Whenever Sentry of Kollis Gate is dealt damage, put a +1/+1 counter on each other creature you control.

{T}: Add {C}.
{T}, Reappropriate: Add {U} or {B}. (Exile exactly two cards from your hand and/or graveyard.)

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
{2}{U}: Return Sequester to its owner's hand.