You've probably heard of the Daily UI challenge, an email list which sends a daily prompt to challenge you to design a specific UI element. It's become really popular, and Dribbble is regularly flooded with entries from Daily UI.
As you can imagine, there's some great work that comes from the challenge, with a lot of inspiration to be taken. Luckily Collect UI collects the best submissions from #DailyUI and curates them into an easy to read website.
Such a good site if you're looking for inspiration on a specific UI element.