I used to go to a Mexican restaurant in Palo Alto, Ca, Riviera Del Mar, that specialized in what they called Mexican Riviera cuisine, the Southern Gulf coast.
Very different from the more common food, which tends to feature border style.
When I went to MIT—having grown up in Southern Arizona—I got some Mexican food. It included black beans.
That surprised me, because Arizona and Sonoran food only included pinto beans.
Since then, I’ve had New Mexico and Texas-style Mexican food as well. But I still prefer Sonoran and Arizona Mexican food!