You can find all sprites rejected during the remoderation here. The original names of each archive are preserved, so you might have some trouble finding the one you need, but all of them should be there. Sadly, nobody kept track of the contents of the archives, so you'll just have to look.
Rejected waiting sprites are entirely removed from the site - you're best off asking the moderator who rejected them to see if they have it. You should, of course, keep in mind that they were likely rejected for a reason. Even if the moderator does have the sprite, you should be careful when using it. You can also ask the author of the sprite.