msem-instigator

Reveal the bottom four cards of your library. Choose up to one permanent card with mana value 3 or less from among them and put it onto the battlefield. Put the rest on the bottom of your library in any order.

Look at the top four cards of your library. You may put a land card from among them onto the battlefield tapped, then put the rest into your graveyard.

Target opponent reveals their hand. You choose a nonland card from it and exile that card.
Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Target opponent reveals their hand. You choose a nonland card from it. That player exiles that card.
Each player conjures a card named Data-Point into their hand. (It's a sorcery that costs {2} with “Draw a card.”)

Prevent all damage that would be dealt by creatures this turn.

Menace
Sacrifice another artifact: Scrap Buggy becomes an artifact creature until end of turn.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

Target player discards a card. If they didn't discard an artifact card, you gain 3 life.

Embellish {3}{B} (If you cast this spell for {3}{B}, create a 1/1 blue Thopter artifact creature token with flying when it enters.)
When Scrap Spiral enters, target creature gets -2/-2 until end of turn.
{3}{B}, {T}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.

Scrap, the Second Myr has all activated abilities of other artifact creatures you control.

When Scrapgear Contraption dies, you may put a +1/+1 counter on target creature.

Vigilance, trample

Flying
Dragon spells and Adventure spells you cast cost {1} less to cast.

Look at the top X cards of your library, where X is the number of instant and sorcery cards in your graveyard. You may reveal an instant or sorcery card from among them and put it on top of your library. Then put the rest on the bottom of your library in a random order.

When Scrapyard Aberration enters, you may sacrifice another artifact. If you do, target creature gets -2/-2 until end of turn.

Sacrifice Scrapyard Raiders: Target artifact gains indestructible until end of turn.

{3}{B}, Exile Screeching Duneborn from your graveyard: You gain 1 life and draw a card.

When Scribal Puppeteer enters, create two 1/1 black Puppet creature tokens with “At the beginning of your upkeep, you lose 1 life.”

Trample, prowess

Ward {2}
Once each turn, if you would create one or more tokens, create that many of those tokens plus one instead.

Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Scribe of the Sky Scrolls. If you spent four or more mana to cast that spell, Scribe of the Sky Scrolls gains flying until end of turn.

Whenever you cast a spell with mana value greater than Script Jockey's power, put a +1/+1 counter on Script Jockey.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create two 1/1 white Human creature tokens.
II — Put a vigilance counter on target creature you control. It becomes a legendary God in addition to its other types.
III — Exile target creature an opponent controls that's a God or that has power 4 or greater.

When Scrivener of Sha'Iv enters, draw a card and adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)

Scrollsnatcher can't block and can't be blocked.
Whenever Scrollsnatcher deals combat damage to a player, look at the top card of each library, then put any number of those cards into their owner's graveyards.

Haste
Frenzy 2 (Whenever this creature attacks and isn't blocked, it gets +2/+0 until end of turn.)