Magento2 Sampletheme.
Run the following commands:
php bin/magento setup:upgrade
php bin/magento setup:static-content:deploy
php bin/magento cache:clean
Now You can set New Theme from Admin Panel
Content->Design->Configuration->Edit->Default Theme->Applied Theme->Select Your New Theme->Save Configuraton.
Supports : Magento 2.0.x, 2.1.x, 2.2.x, 2.3.x and 2.4.x