Inalla, Archmage Ritualist + Spellseeker + Culling the Weak + 7 more

Cast Spellseeker, stacking Inalla's trigger under Spellseeker's ETB trigger.

Tutor Culling the Weak to hand with Spellseeker's ability.

Cast Culling the Weak, sacrificing Spellseeker and adding .

Resolve and pay for the Inalla trigger from earlier, creating a token copy of Spellseeker and leaving floating.

When the token ETBs, tutor Unearth to your hand.

Unearth Spellseeker, leaving floating.

Shortcut resolving both Inalla's trigger and Spellseeker's ETB, tutoring for Burnt Offering and Finale of Promise, leaving floating.

Cast Burnt Offering, sacrificing Spellseeker and adding .

Use that mana to cast Finale of Promise with X=1 targeting Unearth and Culling the Weak.

Sacrifice a Spellseeker token to Culling the Weak for and Unearth Spellseeker.

Resolve Spellseeker's ETB and Inalla's trigger, tutoring Entomb and Reanimate into hand.

Entomb and then Reanimate Archaeomancer, leaving floating.

Resolve Archaeomancer's ETB, returning Burnt Offering from your graveyard to your hand.

Cast Burnt Offering on Archaeomancer, adding .

Resolve the Inalla trigger from when Archaeomancer ETB'd and return Reanimate to your hand, leaving floating.

Reanimate Archaeomancer and resolve the Inalla trigger, retrieving Burnt Offering and FInale of promise, floating.

Sacrifice Archaeomancer to Burnt Offering, adding .

Cast FInale of Promise with X=1 targeting Entomb and Reanimate.

Entomb Shallow Grave and Reanimate Archaeomancer, floating.

Resolve the Archaeomancer trigger returning Burnt Offering from your graveyard to your hand.

Sacrifice Archaeomancer to Burnt Offering, adding .

Resolve the Inalla trigger, making a token copy of Archaeomancer with haste and leaving floating.

Return Shallow Grave with the token copy's ETB.

Cast Shallow Grave targeting Archaeomancer, leaving floating.

Repeat steps 20-24 for infinite hasty Archaeomancers.