This is a Dark theme inspired by Gloom Dark. In order to achieve the result of the screenshot, check this VSCode pull request from Github. Also, this theme was intended to be used with a dark Wallpaper.
The font family used was SF Mono Semibold (weight 500) with ligatures, available here.
Icon theme used: Seedling Icon theme
Here are my VSCode Settings.
Here is the CSS of my workbench.main.css file.