For CalDav/CardDav there's DAVx⁵. It's on Play if you want to support the developer, or F-Droid if you don't.
There is also ICSx⁵ from the same developer, works against outlook.com.
I paid for both, they work great.
There is also ICSx⁵ from the same developer, works against outlook.com.
I paid for both, they work great.