How about "Delete". Something to let the mods now they can delete the thread. I know we have "Sold" but seems kinda weird to put "Sold" on a thread that started as "WTB".
For sold items...Sold: If you sell your item, please edit the prefix to "Sold" and
keep your original title. Do not rename your thread to "Sold" or
"Delete" as the old guidelines suggested.
The mods don't delete "Sold" JY threads like they used to, so I guess in the case of a finished WTB, maybe something like "Found" or "Done" might work.