Door, window, leak, siren, motion and many many more type of sensors. Now you have long range Z-Wave coming out too for extra flexibility.

Battery life is great, it's a mesh network, and you can customize to your heart's content if you're willing to put in the time. Also will not interfere with Wi-Fi signal.

If you want something simple and don't want to spend any time, just start with one of the mass consumer ecosystems that's out there