Use APKPure App
Get Callertone old version APK for Android
Generate custom ringtones for each contact!
This app generates a custom ringtone for each contact, based on their phone number.
You can choose between an iMelody file or a simple monophonic sine synthesizer.
After a while you will start to recognize the ringtone and know who's calling.
If you want anything added or changed, just send an email to callertone@qrk.nl