Kappa Cannoneer + Animation Module + Phyrexian Altar

Kappa Cannoneer

Animation Module

Phyrexian Altar

How it works

1. Cause an artifact to enter the battlefield under you control.
2. The artifact enters the battlefield, triggering Kappa Cannoneer, putting a +1/+1 counter on it and making it unblockable this turn.
3. Animation Module triggers, causing you to pay 1 to create a 1/1 Servo artifact creature token.
4. The Servo enters the battlefield, triggering Kappa Cannoneer.
5. Holding priority, activate Phyrexian Altar by sacrificing the Servo, adding one mana of any color.
6. Resolve the Kappa Cannoneer trigger, putting a +1/+1 counter on it and making it unblockable this turn.
7. Repeat from step 3.