Tacos al carbón: Though fewer and fewer places actually use carbón (charcoal), this is the name for tacos of grilled or griddled meat, often with nopales (cactus paddles) for vegetarians. These are usually served very simply—meat and tortillas—but with lots of salsas and garnishes on offer. At Los Picudos, try a costra, a variation that emerged in Mexico City in the ‘90s, where a crisp-chewy "tortilla" of browned melted cheese is fused to, or wrapped around, the filling.

Tacos de fritanga: In Mexico City, the phrase "tacos de fritanga" is essentially synonymous with "tacos." It refers to meat cuts, mostly from the head or innards (and mostly pork), which are long-cooked in a mix of oil, rendered fat and meat juices. The taquero at El Borrego Viudo mans a large, round, shallow tray with a moat of bubbling liquid (the meat is neither deep-fried nor braised, but essentially both), with a convex hump in the middle for draining oil and heating tortillas.

Tacos de guisado: Guisado translates to "stewed," and these premade fillings, usually in photogenic clay cazuelas, are dolloped deliciously (if unceremoniously) on tortillas at Tacos Hola. This is usually the best taco option for vegetarians and vegetable-lovers; the vegetable-based fillings—such as spicy cauliflower, cheese-stuffed poblano chiles, or tomatillo-braised chard—are often the most interesting. Choose rice or beans as a base for the filling for a heartier taco.

Tacos de carnitas: Mexico didn't have pigs until the Spanish brought them in the 16th century, but one wouldn't know it by the ubiquity of pork in the taco world. Carnitas refers to pork long-cooked in its fat, but since there is such variety among pork cuts, it includes everything from lean loin and leg (maciza) to juicy ribs (costilla) and pork skin (cueritos). At Los Panchos, try a taco de achicalada, made with meat bits from the bottom of the cooking vat—said to be the perfect hangover cure.

Tacos dorados: Tacos dorados ("golden tacos")—aka taquitos or flautas—are deep fried until crispy. These tacos are garnished generously with some combination of salsa, crumbled cheese, cream, onion and lettuce. Because of the logistics of deep frying, taquerías like El Rey de las Ahogadas that specialize in tacos dorados are usually indoors with full kitchens. A delicious new variant is the flauta ahogada ("drowned"), where the crisp taco is partially submerged in a bowl of salsa.

Tacos al pastor: It's no coincidence that tacos al pastor so closely resemble Middle Eastern shawarma. This taco was introduced in the 1960s by descendants of over 100,000 Lebanese who immigrated to Mexico from the 1890s to the 1920s. Tacos al pastor are made from chile and spice-marinated pork, sliced off a vertical rotating spit and placed in small corn tortillas with onion, cilantro, and grilled pineapple. At El Huequito, combine it with bright salsas and a squeeze of lime.