dannys712@deployment-deploy01:~$ foreachwiki sql.php --query="SELECT GROUP_CONCAT(DISTINCT ug_group) AS 'groups' FROM user_groups WHERE ug_group NOT IN ('bot', 'sysop', 'interface-admin', 'bureaucrat', 'steward', 'accountcreator', 'import', 'transwiki', 'ipblock-exempt', 'oversight', 'confirmed', 'flow-bot', 'abusefilter', 'checkuser')" --json
finds all user groups in use that are not common to all wikis. Via the api (eg https://commons.wikimedia.beta.wmflabs.org/w/api.php?action=query&meta=siteinfo&siprop=usergroups) we can check for if a group is defined
Groups with members in the database that don't exist:
enwiki - autoreview (separate from the existing autoreviewer group)
enwiki - suppress (see T112147 and T151688)
fawiki - uploader
fawiki - autopatrol (separate from the existing autopatrolled group)
testwiki - autoreview
testwiki - editor
testwiki - suppress
Additionally, while autoconfirmed is a valid group, it is an implicit one, so there should be no records for it in the database
dannys712@deployment-deploy01:~$ mwscript sql.php --wiki=zhwiki --query="SELECT COUNT(*) FROM user_groups WHERE ug_group = 'autoconfirmed'" --json [ { "COUNT(*)": "3" } ]
since the emptyUserGroup script is based on entries in the database, it should be fine to use that for autoconfirmed too
zhwiki - autoconfirmed