Gilder Bairn + Cryptic Trilobite + Paradise Mantle

Gilder Bairn

Cryptic Trilobite

Paradise Mantle

How it works

1. Activate Gilder Bairn by tapping it, adding G/U.
2. Activate Gilder Bairn by paying 2G/U and untapping it, doubling each counter on Cryptic Trilobite.
3. Activate Cryptic Trilobite's first ability by removing a +1/+1 counter from it, adding CC that can only be spent to activate abilities.
4. Repeat.
5. Once you have infinite +1/+1 counters on Cryptic Trilobite, you may instead double the counters on any other permanent(s).

This clever pairing turns Gilder Bairn into an exponential growth engine by leaning entirely on the untap symbol's synergy with activated abilities. By equipping Paradise Mantle to Gilder Bairn, it gains the tap ability needed to help fund its own untap cost, while Cryptic Trilobite steps in as both the mana source and the counter repository. Removing a +1/+1 counter from Cryptic Trilobite generates the restricted colorless mana required to pay for Gilder Bairn's ability, which in turn doubles the remaining counters on Cryptic Trilobite to leave you with a net surplus. Once this engine spins out of control, you are left with infinite colorless mana for abilities and infinite +1/+1 counters to spread across your battlefield.