[jhvkjhk]

I personally use Ultrasonic. It doesn't look as good as Symfonium, but it's usable and open source: https://gitlab.com/ultrasonic/ultrasonic

[sphars]

I use Ultrasonic as well, but I've found Symfonium to be much more stable, especially wrt Android Auto and Chromecasts.

There's several other open source Android apps as well. I've been testing out as many apps as I can find and documenting the features of each in this spreadsheet[0]. It's a bit out of date, and there's one or two more apps to add, but you get the gist

[0]: https://docs.google.com/spreadsheets/d/1Lr788M1pM3AFOpjR8CRA...