Some months back this repo on github had made a good looking vscode dark islands theme: https://github.com/bwya77/vscode-dark-islands

This "extension" however relied on a different extension that helped load in custom css alongside doing a bunch of unnecessary code patching to other parts of vscode. Not to mention, the install script permanently modified your settings.json file and completely changed it.

I forked a safer version of the theme that simply provides a CSS file and relies on a super minimal extension that simply inlines the custom CSS into one of VSCode's html files. Try it here: https://github.com/raaid3/vscode-dark-islands/forks