Send emails to your users when they reach a certain amount of points or "milestones". This code example sends emails at three milestones: 100 points, 200 points and 300 points. Paste into your child theme's functions.php file.

mycred-email-notice-milestones

/**
 * Add Custom Email Instances
 * First we add in our custom instances so we can select them when we create
 * a new email notice.
 * @version 1.0
 */
add_filter( 'mycred_email_instances', 'mycred_pro_add_milestone_email_instances' );
function mycred_pro_add_milestone_email_instances( $instances ) {

	$instances['accountnum'] = array(
		'label' => 'Point Milestones',
		'100'   => 'Reached 100 points',
		'200'   => 'Reached 200 points',
		'300'   => 'Reached 300 points',
		'end'   => ''
	);

	return $instances;

}

/**
 * Detect Instnaces
 * Next we will need to "detect" when a user reaches each milestone. To prevent
 * them from getting emails each time they gain points over a milestone we save
 * a marker.
 * @version 1.0
 */
add_filter( 'mycred_get_email_events', 'mycred_pro_detect_custom_email_instances', 10, 3 );
function mycred_pro_detect_custom_email_instances( $events, $request, $mycred ) {

	extract( $request );

	$users_balance = $mycred->get_users_balance( $user_id, $type );

	if ( $users_balance > 100 && get_user_meta( $user_id, 'got_for_hundred', true ) == '' ) {
		$events[] = 'accountnum|100';
		add_user_meta( $user_id, 'got_for_hundred', time() );
	}

	if ( $users_balance > 200 && get_user_meta( $user_id, 'got_for_twohundred', true ) == '' ) {
		$events[] = 'accountnum|200';
		add_user_meta( $user_id, 'got_for_twohundred', time() );
	}

	if ( $users_balance > 300 && get_user_meta( $user_id, 'got_for_threehundred', true ) == '' ) {
		$events[] = 'accountnum|300';
		add_user_meta( $user_id, 'got_for_threehundred', time() );
	}

	return $events;

}

@welshlamb10

Unfortunately I am unsure this still works with the current version of myCRED as I am no longer involved with the plugin since 2018. The code was written for older version.