Hi there,
You don’t have to download them all, you can just install the needed addons. The easier way to get them all at once is to download the zip package from ThemeForest and extract it. Then find the add-ons from extension folder, you can then extract the addons and upload to your plugin folder through FTP.
Installing add-ons through Admin may take a while since you’ll do it one by one. FTP is recommended when uploading multiple plugins.
Thanks!