I bought some "fridge magnets" made from neodymium a while back. They're not super strong and pretty small. But the toddler has discovered magnets and I remember the packaging warning to wear safety glasses around them due to "shatter risk." Even this small? I've put them away for now.

Very incompatible with toddlers apparently. And they do shatter into small bits on a hard kitchen floor. Not especially sharp but hard to clean up.