I have used Yoga Nidra with some success -- specifically via InsightTimer, with best meditations by Grace Warlick and Hilary Jackendoff. But lately I've been doing tapping meditations on the Breethe app before bed (sometimes outside on the chaise lounge in the back yard) followed by bedtime hypnotherapy, also amply offered on Breethe. The latter is intense, and usually works (except, as I'm sure fellow insomniacs can relate to, when it doesn't).