Voltaic Construct + Ashnod's Transmogrant + Bloom Tender

Voltaic Construct

Ashnod's Transmogrant

Bloom Tender

How it works

1. Cause Bloom Tender to become an artifact using Ashnod's Transmogrant.
2. Activate Bloom Tender by tapping it, adding at least 3
3. Activate Voltaic Construct by paying 2, untapping Bloom Tender.
4. Repeat from step 2.

To pull off this infinite mana loop, you first need to make your Bloom Tender an artifact creature by sacrificing Ashnod's Transmogrant to permanently add a +1/+1 counter and its new type. Once transformed, tapping Bloom Tender yields enough mana to comfortably pay the activation cost of Voltaic Construct. This untaps your newly minted artifact creature, leaving you with a net gain of mana each cycle and ready to repeat the process indefinitely.