MMDeveloper

Easy to use plugin, that blocks access to your wp-admin area by country. Uses geoip-api-php as the library to work out the visitor’s country.

Admin Block Country

It would be great to be able to redirect to a page 404

Good choice

Block access to your admin pages by country.

Sovit Tamrakar

World Flag is WordPress Flag Plugin which will ease the writer/authors to add flags to posts or pages with shortcode.
Tinymce Editor button has been added to ease the usage of plugin with few clicks of button.

World Flag

World Flag - Country Flag using shortcode.

Admin Block Country vs World Flag