These kings were knocked off their thrones by various friends, relatives, and acquaintances. Some stay pining for their lost monarchies, while others have moved on: Kronos founded a yoga studio in Athens, while Anu creates Japanese zen gardens.
Zeus did his daddy wrong by kicking him off his throne on Mt. Olympus. Never a fan of the man who swallowed his five older siblings, Zeus sent Kronos packing. Then he and his sibs became the next generations of Greek gods.
The Hurrian gods of the ancient Near East got shoved out on a regular basis. First, a duo of divinities had ruled over the Earth. Then, the god Kumarbi battled it out with Anu for control over all things human and divine, even going so far as to bite off Anu's private parts to get him to surrender. Ouch.
Talk about good grandkids! Numitor, king of Alba Longa in Italy, was the grandfather of those lupine twins Romulus and Remus. When R&R were young, Numy was shoved off his throne by his brother, Amulius; R&R later bumped off Amulius and put Grandpa back in his rightful place.