Clearing blocked contact numbers

To get the overview, and manage blocked phone numbers, go to:

Settings -> Phone -> Blocked Contacts.

Press Edit in the upper right corner to remove the numbers you do not want to be blocked anymore

Yes, that feature is not available. You can always send Apple a feedback, who knows - maybe the opportunity will come out in the future.

Feedback to Apple

Product Feedback - Apple

Texan 308, if you have a number of blocked numbers you wish to remove from your list, you have to do them one by one. 🥴

Unfortunately Apple have not caught up by having a select all option. 😡