All of the assets listed on my account here are public domain. I also keep all of the code for my games in open repositories. https://github.com/geraldfingburke
Essentially, I wouldn't say I have a large body of work in the public domain, but I don't have a large body of work. In terms of ratios, everything I've drawn, written, coded, or recorded is in the public domain. The only stuff that isn't listed as public domain is stuff that relies on CC stuff, and you generally can't have a more or less permissive license than the licensor.