Switch - Group switch control
Dimmer - Group level/switch control
Colorful Light - Group colour/level/switch control
Power Meter - Averaged total power usage for group with High/Medium/Low usage indicator based on previous data (Experimental, possibly very inaccurate)
More information is better found here:
https://community.smartthings.com/t/release-trend-setter/31286
The SmartApp seems to be quite popular now so I thought I would submit it for publication as some people aren't keen on having to install multiple SmartApps and Device Handlers.