1/ pttrns

This website provides patterns for various pages and features you would need for an app.

2/ Pinterest

This website is a digital mood-board that displays artworks, photographs and other images posted by designers all over the world. (also known as inspiration.)

3/ Fontsquirrel

A database for fonts, web and print compatible with licensing.

4/ UI Patterns

Another database for UX design patterns, this one goes into more detail about particular application design features.

5/ IOS Patterns

Another database for iPhone interface patterns

6/ Pop by Marvel

This is an app/website that allows the user to upload sketch wireframes to create an interactive prototype.

7/ Marvel

A website that allows the user to turn wireframes into an interactive application prototype.

8/ Behance

Similar to Pinterest, Behance is a database that allows the public to view works by designers but also upload their own.