Your past clients might also be using this strange time to finish up some old projects or get moving on some new ones.
Shoot them a quick email along these lines:
Hey [name],
I hope you and your family are staying safe during these uncertain times.
Just wanted to drop you a quick message in case you’re working from home and looking to get ahead on some projects.
I have more availability than expected so let me know if there’s anything I can help with.