There are more, I've done projects/experiments in a bunch of these areas.
Hey entropy, would love to meetup and talk ideas. I too am a full-stack engineer in SF. Are you free today?
I'd be down to meet-up for a coffee and chat. Email me dan [at] techendo [dot] com
I'm a technical person myself and working with my partners on an idea in healthcare. I'd be happy to meet up to chat. Email me dathoang [at] gmail [dot] com.
In health care there is a LOT going on and it could really push your limits in terms of your technical skills - especially within hospital health care and global health / global health policy arena. It also requires you to partner up with a health care professional which makes for an interesting viewpoint beyond SF tech :)