HOP_PLUGIN_BASE_FOLDERS

Set this variable to point Hop to a comma separated list of folders where you want Hop to look for additional plugins.

When using this variable it will also unset your default plugins folder, make sure to add the default plugin folder to the comma separated list. This can be a relative path to the installation eg. export HOP_PLUGIN_BASE_FOLDERS=./plugins,/additional/plugin/folder.
The ./plugins will point to the plugins in the base installation folder