Gruvbox dark theme for xfce4-terminal (put this in ~/.xfce4/config/terminal/terminalrc)

gruvbox.theme

ColorForeground=#f2f2e5e5bcbc
ColorBackground=#323230302f2f
ColorCursor=#d65bc4cd8ca1
ColorPalette=#323230302f2f;#cccc24241d1d;#989897971a1a;#d7d799992121;#454585858888;#b1b162628686;#68689d9d6a6a;#929283837474;#1d1d20202121;#fbfb49493434;#b8b8bbbb2626;#fafabdbd2f2f;#8383a5a59898;#d3d386869b9b;#8e8ec0c07c7c;#b9b9a6a69393

For the "hard contrast" version:

ColorBackground=#1d1d20202121 

For anyone reading this in the future, it seems that (at least when using xfce4-terminal on Xubuntu) terminalrc is now located at: ~/.config/xfce4/terminal/terminalrc.

Happy hacking.

EDIT: 2018-06-29: I couldn't find the proper directory so I searched around online until I came across a post made by myself from only two months ago with the solution ... woooah.

For xfce4-session 4.16.0 (Xfce 4.16)

For people on 2021.

Create a new archive in /usr/share/xfce4/terminal/colorschemes and call it gruvbox.theme (or whatever you want to name it as long as it ends up in .theme)

doas nano /usr/share/xfce4/terminal/colorschemes/gruvbox.theme

Now, in the file, you're going to paste this.

[Scheme]
Name=Gruvbox
ColorForeground=#f2f2e5e5bcbc
ColorBackground=#323230302f2f
ColorCursor=#d65bc4cd8ca1
ColorPalette=#323230302f2f;#cccc24241d1d;#989897971a1a;#d7d799992121;#45458585>

And that's it, you save it and now you have the theme for the latest version.