Uninstalling a plugin: delete all options with specific prefix

Replace “myplugin_” with your prefix:

global $wpdb;

$plugin_options = $wpdb->get_results( "SELECT option_name FROM $wpdb->options WHERE option_name LIKE 'myplugin_%'" );

foreach( $plugin_options as $option ) {
    delete_option( $option->option_name );
}