I got the most lasting value out of the free UCLA Marc guided meditation sessions[0] which now have an app. When I first used them years ago it was only a list of recordings on a web page. In that time I've tried a few of the other apps that have popped up, and was grandfathered into the Waking Up lifetime membership, but I always think that MARC gave me more lasting benefit than, for instance, the guided meditations in Waking Up. However, this could be due to MARC being my first real introduction into meditation practice that I stuck with, and the others would never have that chance.
Oh cool, I'd almost forgotten about those guided meditations! I used to listen to them a fair bit, not sure what happened to that habit. But good to know that they have an app now, thanks for the info!
[0] https://www.uclahealth.org/marc/mindful-meditations