I'm not sure it's easy to find anyone willing to fund you to work on anything... But, Mozilla is a non-profit, while I worked there I worked exclusively on fre

I'm not sure it's easy to find anyone willing to fund you to work on anything... But, Mozilla is a non-profit, while I worked there I worked exclusively on free software. And the health insurance fantastic. Much of what you work on a GitLab, Facebook, Google, Microsoft, Redhat, etc. is also open source, depending on what team you join.