Suites : Layouts that take up the most space on your desktop and include all commonly needed information and features.
Time and Date : Analog/Digital Clocks and Calendars.
Weather : Climate and temperature related stuff.
Multimedia : Players, volume controllers, anything else related to audio, video or images.
Feed Readers : AKA RSS readers. (news, email, facebook feeds, etc... .)
Network : Network related tools and monitoring systems.
Disk Space : Get information about capacity and specifications of your hard disk/flash drives, file and folders.
Side Bars : They are designed to sit on left or right side of your screen.
Horizontal Bars : If you need some skin to fill top or bottom of your screen.
Search Bars : Search your computer, Google, Bing, Wikipedia and etc from your desktop.
Launchers : Easily access your favorite programs and folders on your desktop.
System Information : They provide information related to hardware devices of your computer system.
Minimal : Very small and tiny skins.
Other : Any skin not related to other categories.
Beta - Previews : Beta version and Previews of skins that are going to be released soon or are still in beta stage.
Icon Sets : What Rainmeter skin designers need the most, extremely helpful if you are going to design launchers.
Screenshots : Show us what you've accomplished with Rainmeter on your desktop.