Some Android phones have microSD card slots, others don’t. But most have USB ports (with maybe one notable exception). That means you can plug in a USB flash drive if you can find one with a phone-sized connector, or if you use a USB OTG adapter.
But what if you want to go old school?
Well, as YouTuber Lazy Game Reviews discovered, you can also use the USB port to connect a floppy disk drive… and play classic games or run apps from that drive. Sure, there’s probably no reason you’d want to do that, but it’s pretty cool to know you can.
In terms of hardware, you just need a USB floppy disk drive and a USB OTG connector (micro USB or USB Type-C, depending on your phone), and a floppy disk.
Plug in the disk drive, insert a disk, and modern Android phone should be able to read data from the disk. You can then copy data to and from the drive or run applications.
Since Lazy Game Reviews is focused on gaming, the YouTube video shows how to load classic PC game Commander Keen onto a floppy drive and then use DOSBox to load and run the game on a phone.
The smarter way to do that is probably just to download the game from the internet, copy it to your phone’s internal storage, and then use DOSBox to load it. But there’s something kind of fascinating about using retro hardware to play a retro game.
LGR seems to agree, because if you stick with the video, at the 7:40 mark you’ll see something even wackier: he uses a USB hub and a PS/2 adapter to plug in an IBM keyboard and the floppy drive at the same time in order to play the game using a physical keyboard.