I'm working on a service that texts you when one of your preloaded accounts sees a change in balance - for example, public transit or toll roads. I've got three services supported so far: https://balancebeamapp.com/

I think it's cool because I login to these accounts very infrequently and months later I have no idea what balance I'm carrying, whether I'll be able to board the bus in a city I'm visiting, etc. Also, the websites are usually not great to use especially on mobile.