Some others I like to do are clamshells - standing hip extensions with a rubber donut around both ankles or a cable machine - side steps with a rubber donut around both ankles, or standing hip adductions with a cable machine or donut - and hip dips standing on a step or bench. From the hip dips you can progress to single leg step-downs or single leg squats, once you're strong enough to do them without letting your knee drop in.

It looks kind of funny, but if you slap yourself on the butt before initiating a glute extension, it really helps you activate it and avoid letting the hammies take over.