A simple app to see iPhone battery level on Apple Watch. Also, leave your Apple Watch charging in another room, and get a notification on your iPhone when it's above 90%. Lots of customizable options.
Easily monitor your hydration and drink more water without tracking intake. Just tap your Apple Watch while you're walking to the bathroom, and get reminders to drink water when it's been a long time since you peed. Averages show trends over time.