IIRC there are non-google app stores from amazon and samsung, but to me using them would defeat the whole purpose of de-googling in the first place, so I stick to the f-droid “store” where all apps available (which is few, compared to what the walled gardens offer) are free (as in both gratis and libre, though some still have “anti-features”). Some of them accept bitcoin donations, etc. Regarding minecraft in particular, there is a clone called freeminer available, but I haven’t tried it.