Apple - My SD card is not showing up in Finder

In the Finder's sidebar, there should be a section called 'Devices'. Click on the one that's your computer's name and you should see the SD card. Drag it back to the sidebar.

I found that removing the SD card, then restarting, then putting the card back in after complete restart worked fine for me.

In my case it did not show up because the name was blank. I use disk utility to name it.