At the beginning of your combat phase, Maester Seymour triggers, putting at least five +1/+1 counters on Sage of Hours.
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 each turn.

Infinite turns

Maester Seymour

Sage of Hours

At the beginning of your combat phase, Maester Seymour triggers, putting at least five +1/+1 counters on Crystalline Crawler.
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

At the beginning of your combat phase, Maester Seymour triggers, putting at least seven +1/+1 counters on Crystalline Crawler.
Declare Hellkite Charger as an attacker, triggering its ability.
Holding priority, activate Crystalline Crawler's first ability seven times by removing seven +1/+1 counters from it, adding {5}{R}{R}.
Resolve the Hellkite Charger trigger, causing you to pay {5}{R}{R} to untap all attacking creatures you control and to get an additional combat phase after this one.
Repeat.

Hellkite Charger

At the beginning of your combat phase, Maester Seymour triggers, putting at least five +1/+1 counters on Crystalline Crawler.
Activate Crystalline Crawler's first ability five times by removing five +1/+1 counters from it, adding {W}{U}{B}{R}{G}.
Activate Najeela by paying {W}{U}{B}{R}{G}, untapping all attacking creatures you control and causing you to get an additional combat phase after this one.
Repeat.

Combos with "Maester Seymour"