Useful site list when you want to learn UI

Pinterest

A site that stores many images useful for the UI. There are more images than any site.

Dribbble

Various designers are posting mainly mobile and web designs as if they were portfolios. There are plenty of modern designs.

Behance

There are more illustrations and industrial products than Dribbble, but it also has a lot of good UI. Since the project is placed like a landing page, it will be a reference for how to attract.

Mobbin

There are many screenshots of the iOS app. Since it is a screen shot of an actual application, it is also suitable for references such as sequences.

UpLabs

There is a "challenges" that redesigns the actual app, and many UIs that you can't usually see are posted. You can also download design files for free, so you can refer to details such as how to make margins.

UI Garage

A screenshot of the latest app is posted. You can search by various search methods such as categories, tags, and platforms.

pttrns

There are screenshots from great old apps to the latest apps. It's great for finding similar applications once you get lost in the design.