1. Canva.com is my favorite design website right now. They offer design templates (such as posters, Twitter header, menus, magazine covers) or you can use your own dimensions. I made that banner using Canva (the pattern is from Lilly Pulitzer though).
2. 10 Minute Mail - I wish I had known about this website a long time ago. You know those times you want to enter an email address for a coupon code and never hear from them again? Or enter an email address to get some sort of freebie sent to you? This email address will destruct within 10 minutes but you can read emails sent to that address for those 10 minutes (for confirmation codes and whatnot).
3. DaFont.com - Download any font you could ever possibly want!
4. r/WritingPrompts - I should have Reddit in general on this list, but this could be useful especially for us writers. Not that I have time to write fiction, but if I wanted to this is where I'd go for ideas!
5. What Should I Read Next? I've asked myself that question way too many times. You just type in authors or books that you like and it will give you suggestions.
6. Coursera allows you to search for free online classes to take. There are literally millions of courses to search through. There are even courses from big universities such as Yale, Princeton, Duke, etc.
7. 3-Minute Journal is a very interesting website that I have yet to try but I'm going to give it a shot this weekend. You write a brief journal entry and it tracks your emotional states, accomplishments, and a lot of other cool things. It shows you a graph over time I believe, too.
8. ListenToYouTube.com - If you do a lot of driving, it might be worthwhile to find some lectures or audiobooks or something to listen to while you're driving or walking to and from classes. John and I do a lot of driving so we listen to neurobiology lectures from Stanford.
9. Weavesilk.com is just incredibly fun to do, I've made some really cool "designs" if you want to call them that. Just try it, you'll see. It's actually kind of therapeutic.
Do you have any "must bookmark" suggestions? I'm always open to new things!