As you can see in below screenshots, I passed through a situation where I failed to find any type of fonts in any folder that actually display icons.

Well, by doing further research I found a solution which I am going to share with all of you.

According to my opinion, if admin-panel’s icon fonts, js and css are missing, then those are not generated properly.

You just need to follow below steps to make it all work:

1. Remove pub/static (Keep .htaccess file back-up and copy it again)
2. Remove var/cache
3. Remove var/composer_home
4. Remove var/generation
5. Remove var/page_cache
6. Remove var/view_preprocessed
7. Run this command : php bin/magento setup:static-content:deploy -f