What flavor are you looking for, Brock? Spicy? Mild?
As I'm sure you're aware, not using onion and or garlic powder in a rub is not common. They're pretty standard ingredients. Just curious...why do you not want them? Allergies/taste preference/or what? I would say go through the Rubs section and pick out one, and just omit the undesired ingredients.
You can also just fall back on a basic brown sugar, kosher salt, black pepper, maybe a little chili powder and paprika type of rub. No need for onion and garlic, if you don't like it.