How do you find those contracts? I don't have all that much of a network, my former colleagues are either still at the startups I left or working for another startup.
My contract work is often “deliver this thing at particular milestones and get it into production by this date”. I politely reject contracts that don’t fit me. I’ve had clients call me back and adjust schedules around my availability as I’ve stipulated I’m already allocated for particular weeks.
Caveats: I’m not a startup guy yet I have started various businesses up.