I have taken two classes involving clay. The first was "Sculpture for non-art-majors," before I was an art major, and the second was ceramics.
I don't know if these fit under the term "significant" or not, but my favorite thing that I made from the first class was a "historical reproduction" of a mayan-looking head that also functioned as a water container. It was the head of a man and on the top there was two spouts that combined into one to pour the water out. I "glazed" it in red iron oxide.
My favorite thing from the second class was our slab project - I made a sailboat and gave it to my mom for Christmas (she likes all things nautical). The bottom was glazed buttery orange and the top was red iron oxide. It sat in a little stand that was shaped like water (I can't remember the glaze of that).
I did take pictures of these, but unfortunately it was before I had my digital camera, so they are not on my computer.
The only works I have done is with modeling clay that falls apart easily and the baking clay. I've done everything from a rose to a miniature human that had clothes shoes hair sneakers and the like.
I don't think I've ever created a significant art object in my life, but I once had access to a device called a 'slab roller', that produced a lovely 3/4" Thick sheet of clay with an amazing canvas texture. I rolled out few feet of that, folded it it over on itself like it was a big ribbon, let it dry, fired it, glazed it, and hung it on the wall. I thought it look amazing.