The reason why I use and love OS X is because of its gorgeous design and simplicity. Although OS X doesn’t give users bunch of customisation options like Windows does, but it is already beautiful. The one thing that you can do in OS X is change the icons of the apps and folders. If you’re wondering how you can change the icons in OS X, you should read this tutorial.
Glacier is a beautiful icon set for Mac designed by Seb Jachec and CJ Melegrito. The icons are clean and minimal and are designed specifically for Yosemite. The icon set includes replacement icons for default apps such as Finder, FaceTime, Calendar. Apart from the app icons, Glacier icons also packs icons for folders in two variants, Graphite and Vibrant.
Though the icons look a lot like the original icons in OS X Yosemite, the icons in Glacier look much more classic and the subtle gradient in the background of the icons looks really nice. Of all the icons in Glacier icons set, I really love the Photos, Launchpad and Safari icon. Also I feel that the Vibrant Folder icons look better than the original folder icons. You can use the LiteIcon Mac app to change the icons.
Glacier icons are free and can be downloaded here.