In addition, if needed, the user search page can be custom modded to not only search user names and locations, but also for items within a user's signature.
note: searching through signatures is already an admin feature through the 7.6.x control panel, iirc. this is not a current feature of the user facing "Search Users" page, but as mentioned, its simple to add.
Last edited by isaac; 08/27/17 08:52 AM. Reason: added more info