All came through personal connections in my network. The developer (now cofounder) is the partner of a friend of mine; the UX designer was part of a circle of friends and colleagues; the designer and one other colleague are both people I had worked with previously.
I think it could be difficult to attract a complete stranger to your startup to work purely for equity. Personal connections come with a foundation of trust and a likely desire to want to help one another.
I strongly recommend anyone building a startup to become an active member of one or more startup communities. It’s fun, rewarding and useful. I highly recommend The Happy Startup School.