Xavier Sal, Infested Captain + Animation Module + Thornbite Staff + Druids' Repository

Xavier Sal, Infested Captain

Animation Module

Thornbite Staff

Druids' Repository

How it works

1. Activate Xavier Sal's second ability by tapping it and sacrificing a creature.
2. When the creature dies, Xavier Sal triggers, untapping Xavier Sal.
3. Resolve the Xavier Sal ability from step 1, putting a +1/+1 counter on a creature you control and a charge counter on Druids' Repository.
4. Animation Module triggers, holding priority, activate Druids' Repository by removing a charge counter from it, adding 1.
5. Resolve the Animation Module trigger, causing you to pay 1 to create a 1/1 Servo artifact creature token.
6. Repeat.
7. Once you have infinite +1/+1 counters among creatures you control, you may instead use Xavier Sal's first ability to get infinite copies of creature tokens you control.

This brilliant engine transforms Xavier Sal, Infested Captain into a rapid-fire machine by equipping him with Thornbite Staff, letting the captain untap every time a creature hits the graveyard. Sacrificing a creature to trigger his proliferate ability also ticks up Druids' Repository with a charge counter from attacking, which then provides the exact mana needed to pay for the trigger from Animation Module. As the Module churns out fresh Servo tokens from the resulting counters, you feed those tokens right back into Xavier Sal's sacrifice loop to sustain the cascade indefinitely.