Thank you for submitting this idea. Can you provide some additional details of what tasks you are performing when searching for usernames? Is this to invite members to the organization, groups or to assign roles?
Thanks for writing up this idea Josef. Kelly - I can provide an example - we use our AGOL site to allow users from different departments and/or organizations to see different maps and apps. We've used a user-naming convention such as "username.division". I'd like to be able to search for all users with a suffix of a division. For example, "*.marketing" and get all the users with that name. See also this idea that is getting at the same concept but with email addresses.