Chrome: The Tabtics extension offers gentle health and productivity reminders, such as "go take an afternoon stroll" and "try to get to sleep earlier tonight" each time you open up a new browser tab.
Along with the tips and motivational quotes, the backgrounds are beautiful too. Tabtics can optionally connect to your Fitbit to add details like how many steps you've taken today and how many hours you slept last night. You'll also see the time and weather in the tab as well.
My only issue with the extension is it only shows the temperature in Celsius and sometimes the tips don't mesh with the weather. For example, Tabtics told me the weather is quite OK so I should go for a walk outside...but it's raining here. I also wish I could refresh the tab or set how often the tab content changes.
Still, it's an elegant, simple, and helpful new tab page.
Tabtics [Chrome Web Store]