At the beginning of your combat phase, Ouroboroid triggers, putting at least five +1/+1 counters on each creature you control.
Activate Sage of Hours by removing all +1/+1 counters from it, causing you to take at least one extra turn after this one.
Repeat.

Infinite turns

Ouroboroid

Sage of Hours

At the beginning of your combat phase, Ouroboroid triggers, putting at least five +1/+1 counters on each creature you control.
Move to your postcombat main phase.
Activate Crystalline Crawler's first ability five times by removing five +1/+1 counters from it, adding {3}{R}{R}.
Activate Aggravated Assault by paying {3}{R}{R}, untapping all creatures you control and causing you to get an additional combat and main phase after this one.
Repeat.

Infinite colored mana

Infinite combat phases

Infinite untap of creatures you control

Infinite mana creatures you control can produce

Infinite +1/+1 counters

Crystalline Crawler

Aggravated Assault

Combos with "Ouroboroid"