From John Paul Palacio - a list and pics of all the different bonus items from the arcade Ghosts 'N Goblins! Here's what he has to say about them:

They can all be acquired through the pots the monsters normally carry, but some of them are pretty rare to come by. The only things the items give you are only extra points ranging from 400 - 5000 points. There are the following items:

pearl necklace - this one is pretty common.

princess' shoe - another common item.

princess' ring (items with a big gem on it) - common

princess' bloomers/underwear - This one gives you 2000 points.

Princess' dress - Rare, and hard to come by. I've only seen this one a few times, but it's point worth is around 1000-4000.

Princess' crown - This one is very rare. I only stumbled upon it once, and it is worth 5000 points.

I think I noticed a feature that separates the NES version of GnG with the arcade version. I noticed how the arcade version does not have the time increase items, but the NES version does. Another thing I noticed is that there are a couple of neat looking statues besides the two or three (if you count the frog king statue) in the arcade version.

I noticed two statues that look like Arthur, and the princess (click here to see the princess statue). There is also a unique statue that looks like a guy with a beard, and glasses, but I was not able to get a photo of it. I saw it after I defeated the Dragon in stage 4, but it disappeared after the key appeared. I would like it if someone could verify the fact that the arcade version might not have the items that increase/decrease time though.

Thanks, John!