We have uncut panels and sheets listed on TCDB. They are scattered throughout the site. Fleer Stickers are a good example. Unfortunately, some collectors have separated them, and now it leaves us with singles and panels/sheets. So, it appears that both singles [because you have just 1] or panel/sheets can both be listed.
Fleer Stickers are just 1 example but there are more.
Remember, Dan said, "Since that's not the way they were officially released, no, the site will not list uncut panels or sheets, unless they were very specifically released in that form."
So, looks like panels and sheets and singles are good to go !