List of common switches :
/master/chrome/common/chrome_switches.cc
List of headless switches :
/master/headless/app/headless_shell_switches.cc
To search other switches :
https://source.chromium.org/search?q=file:switches.cc&ss=chromium%2Fchromium%2Fsrc
List of preferences:
/master/chrome/common/pref_names.cc