Many of the pre-packaged taco seasonings contain gluten. I make my own.
Brown ground beef, bison, or turkey
Midway through the process, add 1/2 diced onion and continue browning
When ground meat is nearly completely browned, add one or two cloves of garlic - either finely diced or pressed through a garlic press
Season with a generous sprinkling of salt, black pepper, and 1/2 to 1 teaspoon cumin. Add a light dusting of dried oregano. Taste and add more seasonings as desired.
ground chili powder, cayenne pepper, or chipolte pepper may be added as desired (I don't usually use these because I avoid nightshades)
Serve on a corn or rice flour shell, sliced black olives, sliced avocado, salsa, diced lettuce, diced tomato, and a squeeze of lime.