Community-contributed Hugo themes, showcased at themes.gohugo.io, are hosted in a centralized GitHub repository. The Hugo Themes Repo itself at github.com/spf13/hugoThemes is really a meta repository which contains pointers to set of contributed themes.
Installing all themes
If you would like to install all of the available Hugo themes, simply clone the entire repository from within your working directory:
$ git clone --recursive https://github.com/spf13/hugoThemes.git themes
Installing a specific theme
$ mkdir themes $ cd themes $ git clone URL_TO_THEME