Can someone help me in guiding available API's or any suitable extension for shipping address verification in magento 2 commerce website.
There are many carriers available in magento marketplace. See few lists
Yes SmartyStreets has address verification APIs that work with Magento2. Here a module I found on GitHub: https://github.com/thinkpyxl/magento2-Pyxl_SmartyStreets
It looks like it still uses SmartyStreets basic autocomplete tool but I would suggest using the Autocomplete Pro API. The basic version is no longer supported.
It shouldn't be too difficult to make the change. The pro version is faster, prioritizes results based on user location, included apartment numbers in the predictions and won't give fake addresses.