Hallmark has been releasing Harry Potter ornaments since 2000, and I hope they don't stop any time soon. I have two (the Hogwarts castle from 2013 and Sorting Hat from 2014) and can attest to the beauty and quality of these ornaments.
I think it is interesting to see the progression of the ornaments. The early Harry Potter ornaments were made of pewter and were smaller than the more recent ones. In 2001 they started making them more realistic and got away from pewter, which is how they continue to be made, and many the more recent ornaments include lights and/or sound and/or movement.
I have listed every ornament Hallmark has produced from their Harry Potter line. The ornaments are first available to buy in July of each year and almost always sell out before Christmas of the year they are released, which means some ornaments, especially the older ones, can be very hard to find. I have included links to both Amazon and eBay to make it easier for you to find what you are looking for.
Do you live outside the United States?
Although some items on Amazon can be shipped world wide, you will probably have the best luck with eBay and Etsy. Click here to see how to know if an item from those three sites can be shipped outside the U.S.A., as well as how you can buy items found and have them shipped to you even if the store you buy from doesn't ship to your country.(Clicking this will open a new window so you won't lose the page you are currently on.)
The Harry Potter collection of Hallmark Christmas ornaments are highly collectible and sell out quickly in most Hallmark stores every year. They can be hard to find in your local neighborhood but you can find them easily on both Amazon and eBay.