They have fillings beyond the typical pork-beef-chicken trinity
Now that we’ve covered tortillas, let’s hit the second component of tacos: the filling. The majority of taco operations trade in the MVPs (most viable products) of pork-beef-chicken. Inoffensive and approachable, the meats come grilled or simmered. This isn’t to dismiss the more common proteins, which can be magnificent when prepared by master taqueros (taco chefs) -- simple, elegant, hit-the-spot munchies dotted with char.
However, these fillings are but a few checkpoints on a potentially limitless lifelong taco bucket list. There are home-style south-of-the-border classics like weenie and eggs, chile relleno, cauliflower fritters, all manner of lamb and goat preparations, roasted grasshoppers, and ant larvae. If you can ingest it it, the stuff has likely already been put in a tortilla in Mexico. Fillings you’re less familiar with are a solid indication the establishment in question has more up its sleeve than your average taqueria.