Pinterest is one of my favorite websites because it provides endless amounts of inspiration for my creative endeavors, and it is designed in such a way that the site's content is immediately available upon opening it, and users are able to organize the content they like in a simple and cleanly designed way.
I like Designspiration for similar reasons, because it is a great resource that can be used for creating mood boards and getting inspiration for graphic design projects, and its design is clean and organized which improves user experience.
Letterboxd is a site that allows you to read and write reviews about movies, and it succeeds at formatting a lot of different information on the screen at once in such a way that is easy to understand and operate.