One of my recent builds was based on the barbed straight sword, but the ring had no effect on that weapon, so I had to scrap it. I just looked at the page, but there's not a lot of info there, so I decided to start a confirmed weapons list.
I added a few weapons I know are confirmed, but also a few unconfirmed. If you have more details on confirmed weapons feel free to add them to the list, or on this page.
The wiki also states that only physical damage is boosted by it, could someone with an int build try the moonlight butterfly horn to confirm?