SpamBlocker on fdroid can block any numbers not saved to your address book. It can even make exceptions for any repeated numbers that aren’t in your contacts but call multiple times within some time period (5min, 30min, whatever). And it can temporarily whitelist a number you dialed recently in case you’re expecting a call-back.
It also has the ability to download spam phone number databases from the internet if you want, but to be honest, I tried setting up that feature and couldn’t figure it out. So while it can use a 3rd party, it isn’t required.
SpamBlocker on fdroid can block any numbers not saved to your address book. It can even make exceptions for any repeated numbers that aren’t in your contacts but call multiple times within some time period (5min, 30min, whatever). And it can temporarily whitelist a number you dialed recently in case you’re expecting a call-back.
It also has the ability to download spam phone number databases from the internet if you want, but to be honest, I tried setting up that feature and couldn’t figure it out. So while it can use a 3rd party, it isn’t required.