Special:ListUsers is a special page that allows you to view all people who have edited a specific wikia. The page gives details such as number of edits, last edited date, date when they were last logged in, and user groups - with several options to filter the list.
To be seen on the default list of active users, a user must have 5+ edits OR belong to 1+ group (sysop, staff, etc.) on that wikia.
You can change the criteria for number of edits by clicking the dropdown menu labeled "Contributed".
Staff, bots, bureaucrats, rollback, and sysops will appear regardless of how many times they've ever contributed on the wikia.
The checkboxes at the top of the page can be checked to see only users from a certain group (for more information on what these groups signify, please see Help:User access levels).
Admins can easily access ListUsers by clicking on "User List" (icon: ) on the Admin Dashboard.
For wikias with a lot of users, it may be useful to use the "Display users at" box to get to users with names that start with later letters at the alphabet, instead of flipping through all the pages to get to the - say "T" or "Z" - section of the page.