Some useful dark themes built around the principal of inverting all the colours of the html document and then rotating the hue by 180°. Works best with Stylus and the Expose iframes via HTML[stylus-iframe] setting enabled.

• Atlassian Cloud
• AWS
• Google
• Jenkins
• LinkedIn

• StackOverflow QandA Highlighting

If you are looking for dark themes for GitHub, StackOverflow and Wikipedia, I recommend these from the good folks over at StylishThemes:

• GitHub
• StackOverflow
• Wikipedia