If you want to find art by an artist, or containing characters that belong to someone with an FA account, but simply searching for their name in the search field doesn't bring up desired results, use this search query:

(@message iconuser) | (@message usericon) | (@message linkuser)

...and replace user with the username that appears in their profile URL.

Examples: Palace, Bayzan, Geordie_79, Aeronus

Very useful in case the artist/owner has a large backlog of art that hasn't been uploaded yet!