These little Neodymium magnets are an interesting size. Small and inexpensive, you can buy a bunch for a low price. They are great for hanging photos, as one or two of them will hold a picture firmly to a metal surface, and they are virtually flat. You can also make these little Rare earth magnets do some strange and interesting things around larger magnets.
Using the flat surfaces on solid steel, we were able to get one of these magnets to hold over 20 lbs. That is over 2000 times the weight of one permanent magnet! Simply amazing!