WordPress test data - markhowellsmead/helpers GitHub Wiki
Full theme unit test data
Run this in the web root. Requires WP CLI.
curl -O https://raw.githubusercontent.com/WPTRT/theme-unit-test/master/themeunittestdata.wordpress.xml
wp plugin install wordpress-importer --activate
wp import ./themeunittestdata.wordpress.xml --authors=create
rm themeunittestdata.wordpress.xml
FakerPress
Plugin, with which you can create or delete random test data (including users etc.)