Jellycons is a free pack of pixel-perfect iOS8 app icons created with Apple Sketch by LoveUI.co.
A vector iPhone 6 mockup made with Sketch. Freebie created and released by Aubrey.
iPhone 6 mockup – Sketch
Here is a clean and minimal UI kit made with Sketch app. Freebie created and released by Mateusz Dembek.
Clean UI Kit for Sketch
An Android L’s tablet UI template for Sketch App. Mobile template is available too. Freebie created and released by Vincent Tantardini.
Android L tablet UI template – Sketch
An Android L’s mobile UI template for Sketch App. Freebie created and released by Vincent Tantardini.
Android L UI template – Sketch
Yosemite UI Kit for Sketch 3. All UI elements (well, besides the OS X 10.10 Icons) have been redrawn and restyled as accurately as possible.