Every SD card I have gotten has arrived in a case. I'm sure there are exceptions, but you can also buy them cheaply (there's a 10-pack for sale as an add-on item for $4.25 at Amazon).
Since realised that I've bought both SD and MicroSD cards with and without cases. A MicroSD got bent in the post, bought as new. And a accidentally put my foot on an SD while shuffling cards.