GUI kits are a very good way to start implementing design on your application. If you are a designer, you know important time is when you need to re-use the same layouts or GUI elements and this web, mobile or application GUI kits that we are sharing today will definitely help you build a consistent and editable layout.
The GUI kits are mainly based on .PSD format but some can be also be found in .PNG format. The list may continue so if you know any other good mobile GUI kits, web GUI kits or application GUI kits please share them in the comment section. To download/demo, simply click on the image preview. All kits listed below are free so enjoy them up.