In a large mixing bowl, combine ground beef, gluten-free breadcrumbs, finely chopped onion, Worcestershire sauce, garlic powder, salt, and pepper using a fork or your hands until just mixed. Allow the mixture to rest for about 10 minutes.

With your hands, gently roll the beef mixture into meatballs, aiming for sizes around 1 to 1.5 inches in diameter. Place them on a tray lined with parchment paper.

Once all the meatballs are formed, carefully place them in the bottom of your slow cooker in a single layer.

Pour the beef broth slowly over the arranged meatballs, ensuring they are mostly submerged.

Cover the crockpot and set it to low heat for 6 hours. Ensure meatballs reach an internal temperature of 165°F.

Once cooked, remove the lid and serve the meatballs warm with some broth over the top.