Out of the box, I love Vanilla OS's color scheme and wallpaper, with Fedora in second place for a default Gnome environment. I like the Pop_OS theme. I use River WM with a gruvbox theme (Vivaldi with no open tabs pictured), which is about as far from out of the box as you can get. Incidentally, I've been team light theme forEVER, but I've switched with gruvbox.