I collect glass knife rests Angela, and I would agree it most likely is one. The beauty of the shape is that it is unlikely to roll on the table.
If you put Knife Rests, Porte Couteaux, and Repose Couteaux in ebay saved searches, eventually you will come across matching ones... I have them on watch all the time and if I see others I will let you know.
I only collect the animal ones, but they all come up in the search engine so I get to see the lot. Usually you only get to know the maker if it is either signed or there is a set in a marked box, so good luck!!