Vera Block is a huge collection of mobile screens and components with trendy design. Each screen and component is made carefully and easily customized for any project. This product will speed up your work in mobile design.
If you are serious about designing interfaces, you should not be using Photoshop.
There are so many tools to choose from that are designed and built specifically for designing interfaces. Here are a few:
Quicker interface design in Photoshop (I guess)
Design a UI kit for other tools like Sketch / AdobeXD, not Photoshop.