Arck Interactive's plugins:
Inspired by upload_users project by Jaakko Naakka (http://community.elgg.org/pg/plugins/release/165550/developer/naakka/upload-users)
This is an upgraded and slightly modified version of upload_users plugin by Jaakko Naakka from Mediamaisteri Group.
This plugin allows you to import CSV files and create new groups with any metadata specified in your CSV.
if you mess it up and want to delete all the groups do the following : Go to cpanle then phpmyadmin
select your database where elgg is installed then find elgg_entities then look into the pages and only delete the object that says groups
I have added an screenshot if needed.