Infinite activations of most planeswalkersInfinite colorless manaInfinite creature tokensInfinite death triggersInfinite creature ETBInfinite creature LTBInfinite mana creatures you control can produceInfinite creature sacrifice triggersInfinite untap of artifacts you controlInfinite untap of creaturesInfinite mana artifacts you control can produce
How it works
Activate Elspeth's first loyalty ability by putting a loyalty counter on it, creating three 1/1 Soldier creature tokens.
When the Soldiers enter the battlefield, Intruder Alarm triggers, untapping all creatures.
Activate Ashnod's Altar twice by sacrificing two Soldiers, adding CCCC.
Activate The Chain Veil by paying 4 and tapping it, allowing an extra activation of your planeswalkers' loyalty abilities this turn.
Activate Aphetto Alchemist by tapping it, untapping The Chain Veil.
Repeat.
This intricate loop turns Elspeth, Sun's Champion into a one-woman army, using her +1 ability to spawn three 1/1 Soldier tokens that immediately trigger Intruder Alarm upon entering the battlefield. That alarm bell untaps all creatures, letting you feed two of those newly minted Soldiers to Ashnod's Altar to generate the exact {4} needed to untap and activate The Chain Veil. Meanwhile, Aphetto Alchemist capitalizes on the global untap effect to repeatedly refresh The Chain Veil, bypassing the usual one-activation-per-turn limit so Elspeth can churn out infinite tokens, mana, and triggers.