I found this really cool website: http://www.tenpacesanddraw.com/
Each week, the people that run the website sets a challenge for designers and illustrators to sketch and swap with others to make cool designs. So the whole website has designs from different people and sketches also.
And you can see all the different challenges that they had. One of the challenges that I like is Character Redesign because they had a Star Wars challenge and all the designs for it are awesome. Also when you design something for a challenge they put your information in like your website so if people like your stuff they get to know more about you. So if you're bored, you can contribute to the website and do one of the challenges!