A new tweak for Google Home makes it easier to access music you've uploaded, even if you're not a Google Play Music subscriber. While Google Play Music customers could already listen to uploaded or purchased music by either selecting it on another device and using the Cast feature or putting it in a playlist, a new update rolling out means you can ask for your tracks directly by voice. It's not active on my account yet even after a device reboot (although I do see the speaker as an available Bluetooth device), but a post in the Home support forum and updated notes on the support page explain how it all works.
A few points to note:
The "Play <genre/mood/activity>" basic voice command isn't supported for uploaded/purchased music.
If Google Play Music isn't your default music player, you need to say "Ok Google, play X <on Google Play Music>" to hear subscription/free radio/uploaded/purchased music. Only personal playlists will be prioritized above your default music player.
This feature is currently rolling out to all regions where Google Home is supported.