This app was mentioned in 3 comments, with an average of 2.33 upvotes
The only thing I've found to be not utterly disappointing, and in fact quite impressive is the JAUNT VR app. They have incredible videos in higher quality than YouTube can stream reliably, and they're actually filmed properly for VR
https://play.google.com/store/apps/details?id=com.jauntvr.android.player.cardboard&hl=en
Just pick among the top videos in Jaunt VR, which are higher-quality than stuff like YouTube, and, I quote directly from the description, "employing 360 degree stereoscopic imagery with directional audio".
Otherwise, FullDive lets you not only play 360° and 3D YouTube video, but specifically shows channels containing only them. Unfortunately, you can browse 360° videos or 3D ones, and there is not an option to only view the ones that are both of those; however, it's easy enough to find one, as shown by this search (one of the first hits it gives for me is this documentary video which is quite definitely both 360° and stereoscopic).
Finally, if one wanted to go there, practically all VR porn is stereoscopic (although most of it is just 180° and not really 360° as that's not often needed, due to... playback contraints), as being flat would definitely degrade the experience; you wouldn't have difficulty finding some of that in this sub if you enable NSFW thread viewing.