We have a great round-up on design & UI collection websites. Usually, you see each inspirational design in static image, but nowadays, since animation has became one of the crucial element in UI design, you can see some of the websites record animation in GIF format and even video to fully demonstrate the effect.
So, if you're looking for inspiration in certain elements that you aren't familiar with, this is the right page to start:
Use Your Interface
A site with UI animations recorded in Gif.

Lovely UI
A collection of mobile ui elements.

UI Parade
Website elements, mobile and animation inspiration.

Inspired UI
Mobile and Tablet design inspirations.

Mobile Patterns
Mobile design grouped in different categories such as list, maps, search etc.

Pattern Tap
Design pattern from zurb.

Wear UI
UI inspiration for wearable.

Little Big Details
Subtle animation in websites.

Hey User
A video gallery for Mobile onboarding design inspiration.

UI from Ultralinx
Design pattern from UltraLinx

UI Movement
See the subtle animations in UI, recorded in Gif too.

UI Haus
A good collection of user contributed UI inspiration.

Grafikr
A collection of animation, UI, mobile and graphic design.

Collect UI
Handpicked design inspirations.

Up Labs
UI resources for designers and developers.

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