Any smart device capable of connecting to internet using wifi or wired is a good candidate for a nice addition to your home automation.
Devices that are not capable to connect and controlled through internet will need smart controllers attached that can either be build yourself or bought off the shelf. Many off the shelf devices comes bundled with their own interfaces or apps to control. We will mainly focus on building our own smart devices or configuring smart devices to work with messaging and automation interface to bring one single unified interface for your home.
Disclaimer: Some off the shelf smart devices may not interact with opensource so ensure to look into open communication/API level access if decide to buy or integrate off the shelf devices.Some prime candidates for home automation (click on links to see available projects):