You would need to copy all of the files and folders for each add-on and then add these to the new forum (assuming you have the licenses to use the add-ons on more than one forum). You would also need the associated XML files to install these add-ons on the new forum. Now unless the add-ons had copies of the XML files within their associated folders (and many don't, they usually have them in the root of the zip file for the add-on, outside of the upload folder for files/folders to upload) then you won't be able to install them.