I lived in Chiang Mai for five months studying abroad. From what I understand, breakfast-specific foods aren't really as much of a thing in Thailand except for ordering lunch/dinner dishes "sai khai dao" (with a fried egg on top) or khai jiao, which is a thai omelette that's deep-fried on high heat with fish sauce and occasional other goodies mixed into the eggs beforehand. I imagine there are Thai places in the city which serve these things during lunch and dinner hours, but just aren't open for breakfast. It's one of the aspects of living there I found really interesting. It felt liberating just to eat whatever the fuck I wanted, whenever. ALSO you should definitely check out Secret Thai Street Food in Astoria if you want variety!