I really like the GM applewood rub on pork (butts, pork steaks, etc).
Since an ingredient list starts with the greatest amounts added, and moves to the least amounts, this rub is lower in salt than many of them out there.
Ingredients: Sugar, spices and herbs (including chili pepper and red pepper), garlic, salt, maltodextrin, onion, silicon dioxide (added to make free flowing), tamarind extract, molasses, apple cider vinegar, natural applewood smoke flavor, malic acid and caramel color.