The Chain Veil + Ashnod's Altar + Ral Zarek + Chandra, Acolyte of Flame

The Chain Veil

Ashnod's Altar

Ral Zarek

Chandra, Acolyte of Flame

How it works

1. Activate Chandra's second loyalty ability by putting a loyalty counter on it, creating two 1/1 Elemental creature tokens.
2. Activate Ashnod's Altar twice by sacrificing the Elementals, adding CCCC.
3. Activate The Chain Veil by paying 4 and tapping it, allowing an extra activation of your planeswalkers' loyalty abilities this turn.
4. Activate Ral Zarek's first loyalty ability by putting a loyalty counter on it, untapping The Chain Veil.
5. Repeat.

This ingenious loop relies on turning planeswalker loyalty into a self-sustaining engine, with Chandra, Acolyte of Flame providing the expendable fuel by creating two 1/1 red Elemental creature tokens that are immediately fed to Ashnod's Altar for the mana needed to keep going. That generated mana pays for The Chain Veil, whose active ability bypasses the normal once-per-turn restriction on planeswalker abilities so Ral Zarek can repeatedly use his +1 to untap The Chain Veil. Because Chandra also pumps her own loyalty with her 0-ability to offset the costs of repetition, this trio creates a perpetual motion machine that lets you endlessly activate your board.