With the Proweblook Phone Validator plugin you can easily verify if a phone number is really valid and callable (https://proweblook.com).

With the Byteplant Phone Validator plugin you can easily verify if a phone number is really valid and callable (https://www.byteplant.com/phone-validator/).

A simple and nice plugin to get auto country flag from user ip address on gravity form phone field.

Add phone input with country flags, dial codes, and validation to WordPress forms and WooCommerce checkout (classic + blocks).