Are there any Muslim or non-believing creatures among the various beasts, birds, and animals, or are they not held accountable?

Animals are not described as Muslim or disbeliever because they lack intellect and are not held accountable. However, they are subservient to God, prostrate to Him, and glorify Him with His praise, like the rest of creation. Allah Almighty says: "And to Allah prostrates whatever is in the heavens and whatever is on the earth of creatures."