Google gives more options for call blocking in an app you might not suspect
Previously, the only option for blocking calls was to add numbers to a call block list from the Phone app's Recent calls page, but now there are four new options for blocking calls. If you want, you can block all calls from numbers that aren't in your contacts list, block calls from private or unknown numbers, or even block calls made from pay phones. That last one is a bit surprising because as mobile phones have taken over and become commonplace, pay phones have slowly been removed from public spaces. There are likely still places around the world with pay phones, but it's been quite a long time since we've seen any in the U.S.
Oddly enough though, the new options won't be found in the Phone app. Instead, Google put the new options in the Contacts app all the way at the bottom of the Settings page, under the Manage contacts header. That will give you toggles for the new call block features as well as a list of numbers you've already blocked.