Falco Spara, Pactweaver + Sensei's Divining Top + Uthros Research Craft + Jhoira's Familiar

Falco Spara, Pactweaver

Sensei's Divining Top

Uthros Research Craft

Jhoira's Familiar

How it works

1. Activate Sensei's Divining Top's second ability by tapping it, causing you to draw a card and put Sensei's Divining Top on top of your library.
2. Cast Sensei's Diving Top from the top of your library by paying 0 and removing a charge counter from Uthros Research Craft.
3. Uthros Research Craft triggers, putting a charge counter on it and causing you to draw a card.
4. Repeat.

This engine turns the humble top of your library into an endless card-drawing machine by turning Sensei's Divining Top into a free, self-replacing spell. Falco Spara, Pactweaver is the linchpin that grants you permission to cast that Top directly from your library while paying its mana cost with a counter instead of mana. To make this loop self-sustaining, Uthros Research Craft steps in with its passive trigger, replenishing the charge counters removed by Falco Spara while replacing the Top you just cast with a fresh card draw. Meanwhile, Jhoira's Familiar isn't strictly necessary for the core loop to function once the mana cost is reduced to zero, but its cost-reduction ability helps smooth out your historic setup before you begin looping.