Iron Spider, Stark Upgrade + Voltaic Construct + Crystalline Crawler + Workhorse

Iron Spider, Stark Upgrade

Voltaic Construct

Crystalline Crawler

Workhorse

How it works

1. Activate Iron Spider by tapping it, putting a +1/+1 counter on each artifact creature and/or Vehicle you control.
2. Activate Workhorse and Crystalline Crawler by removing a +1/+1 counter from each of them, adding 1C.
3. Activate Voltaic Construct by paying 2, untapping Iron Spider.
4. Repeat.

This clever loop turns Iron Spider, Stark Upgrade's tap ability into a self-sustaining engine by leaning on Voltaic Construct to constantly untap it for two mana. To fund those untaps and keep the loop going, Crystalline Crawler and Workhorse pitch the very +1/+1 counters that Iron Spider hands out, converting them into the exact colorless and colored mana you need. Together, these pieces not only fuel the entire mechanism but also grow exponentially larger with every iteration, stacking massive power onto your board.