BP Bulk Delete is a simple plugin that allows BuddyPress Admins to delete all Activity, Notifications and messages older than a specific date. This is aimed primarily at older systems to remove unused database entries.
Notifications
Buddy Notification bell is a BuddyPress plugin that adds a notification marker onto a page based on a shortcode, whenever the user gets a notification and is viewing a page with the shortcode loaded then the notification bell will sound and they will be able to click on the bell in order to view the notification.