Visualping.io is an amazing free web-service that allows you to monitor any webpage and send you an email as soon it changes visually. Also you can set check time interval to hourly, daily or weekly. You can choose trigger from tiny, medium and major change.
Jetpack by WordPress.Com is most popular and widely used plugin offers you stats and various other features. In this article we are sharing list of other popular statistics and visitor maps plugins available in WordPress Plugin Repository.