
So the only decent throwback I use is a Windows 7 theme - with proper colorful icons and the aero glass effects. It's such a shame that as time has passed even the theme creators are only using the same fashions copied from Windows 8 and above. One other theme I wish existed is the mid 00s Mac OS X brushed metal look - iTunes used to have this, and there's XMoon if you want this for PM.
Theme customizations in the 00s were so radical - for Windows XP there were original themes based on the Matrix films, or steampunk themed with dials and metallic highlights among dozens of others. Nothing like that anymore, or the ones you find are no longer compatible.