Optical Drive Emulators (or ODEs for short) are something of a godsend for people who want the flexibility to run games from a microSD card but don't like the idea of software emulation. They effectively replace the physical disc drive of your console, allowing you to experience software as if it were running from the original media, but with the massive benefit of having hundreds of titles at your fingertips.
We've already seen the FPGA-based MODE from Terraionion, but that is both expensive and hard to come by these days, due to part shortages. Thankfully, Twitter user Paulo7x8 has just shown off an alternative: a PlayStation 1 ODE based around the incredibly cheap and popular Raspberry Pi Pico.
Just like the MODE, it reads disc image files from your solid-state media (in this case, a microSD card) and boots them into the PS1, just like a real game. As far as the console is concerned, there's no difference between running the disc image and spinning the actual disc in the drive. There are, of course, legal concerns to take into account here, but if you're comfortable with ripping your own library of games, then this could be of real interest.
The catch is that you can't buy this mod yet. However, Paulo7x8 has confirmed that he plans to make the project open source in the future, so anyone will be able to access the original PCB files and code. When those become live, you'll be able to build your own mod – assuming you have the required talent with a soldering iron.