All 9 Combos with Abstruse Archaic

Ulalek, Fused Atrocity + Writhing Chrysalis + Abstruse Archaic

Infinite Mana: Infinite LTB, Infinite ETB, Infinite sacrifice triggers, Infinite death triggers, Infinite colorless mana, Infinite creature tokens, Infinite +1/+1 counters on an infinite number of creature tokens

Cast Writhing Chrysalis by paying {2}{R}{G}. Writhing Chrysalis and Ulalek trigger. Holding priority, activate Abstruse Archaic by paying {1} and tapping it, copying Ulalek's trigger. Resolve the copied Ulalek trigger, causing you to pay {C}{C} and creating a copy of the Writhing Chrysalis spell, Writhing Chrysalis's trigger, and Ulalek's trigger. Resolve the copied Ulalek trigger, causing you to pay {C}{C} and creating a copy of at least two Writhing Chrysalis spells, at least two Writhing Chrysalis's triggers, and Ulalek's trigger. Resolve a Writhing Chrysalis trigger, creating two Eldrazi Spawn tokens. Activate two Eldrazi Spawn tokens by sacrificing them, adding {C}{C}. Repeat from 5 any number of times. Once you have infinite copies of the spells and triggers, you can resolve them all, activate any number of Eldrazi Spawn tokens, and trigger all Writhing Chrysalis's final abilities.