I think the Minidisc[1] is what you're after - 68mm×72mm (2.7in x 2.8in), 80 minutes of audio/~300MB of data.
I'm always confused by my desire for slightly inconvenient physical formats like this to make a comeback - I suspect it's some combination of 90s nostalgia (I'm mid-40s) and a psychological reaction to the enshitification of culture now being an endless subscription service.
I'm always confused by my desire for slightly inconvenient physical formats like this to make a comeback - I suspect it's some combination of 90s nostalgia (I'm mid-40s) and a psychological reaction to the enshitification of culture now being an endless subscription service.
[1] https://en.wikipedia.org/wiki/MiniDisc