OpenFlops is an Open Source Hardware implementation of the well-known Gotek floppy disk drive emulator/simulator.

OpenFlops connects to your computer's floppy drive connector using a standard floppy data and power cables, and acts like a floppy drive to your computer. You insert a USB thumb drive with your floppy image files, and the OpenFlops will present them to your computer as if they were actual floppy disks.

As per the OpenFlops website, the OpenFlops with FlashFloppy on it has several improvements over the original Gotek.

Usable with many different platforms, including IBM PC, Commodore Amiga, Amstrad CPC, Atari ST, etc.
Directly supports a wide range of image formats, ADF, IMG, IMA, DSK, D81, ST, etc.
Same physical dimensions as Gotek, so will fit the same brackets and mounts
Easily accessible pin headers for connection of a i2c display (either OLED or LCD), rotary encoder (including power)
Built-in amplified speaker, or easily-accessible pin header for an external one
Comes with USB connector mounted, but also be connected to a pin header
Has additional 3.3V, 5V and GND power pins
Flexible track layout for Raw Sector Images
Extremely configurable
Supports AutoSwap for games with a large number of disks
Connected Motor signal
And hey, it's Open Hardware!

Please note, this is only the OpenFlops board itself. It comes with the FlashFloppy firmware already flashed and it is fully functional, but you will need to get the below items if you don't have them already. I sell these items separately, or as an option to this listing, as some people may already have some of the items, and other items differ depending on which hardware you want to connect your OpenFlops to.

These items are needed or recommended in addition to the OpenFlops board:

an I²C OLED display (several sizes available as an option)
a rotary encoder (not strictly necessary, but recommended for easier menu navigation if physical space allows)
a floppy data cable, if you don't have it already
a four-pin floppy power cable -- type depending on your application and power supply
a USB thumb drive for your floppy images
a bracket or case for mounting the board, depending on the computer in which you want to use the OpenFlops.