Now that Auro-3D is a codec that is showing up in receivers, it would be nice to know where to get discs that have Auro-3D music.
2L from Norway is a good source. Here is a list of some of their latest releases. Note that they are also in PCM 24/192 and multi-channel DTS HD-MA.
You can go to the 2L website and listen to samples of the tracks. They are also available as high resolution downloads, but only in PCM and DSD, not Auro-3D.