What are the best apps or websites for design employment opportunities?

I've been on the opposite side so far (posting a project for designers to send a proposal). Design Inc. has one of the best communities of designers I've seen in a long time. Within 2 hours of me posting my project, I had 5 amazing proposals. Within a week, I selected the two designers I wanted to work with. For designers, getting invited to Design Inc. would be an honor and certainly the best way to find freelance or full-time opportunities!

Designer News is a large, global community of people working or interested in design and technology. They have a job board and I think it fits well with what you're looking for. Hope it helps!

Designer resource