If you want to output a minimal HTML file, with no CSS, no Javascript, no preamble or postamble, here are the variable you would need to set:
(setq org-html-head ""
org-html-head-extra ""
org-html-head-include-default-style nil
org-html-head-include-scripts nil
org-html-preamble nil
org-html-postamble nil
org-html-use-infojs nil)