They could be about modern retro games and modern retro synth music (Adlib, SID, PSG audio etc) - and by that I mean games and music targeting the classic platforms but made today. A single 3.5" floppy won't fit many games, but it would fit screenshots and a dozen tunes or so.

It would be the expected text+pics+music. If you charged $2 for it people wouldn't be too interested; if you had a pretty label, simple packaging and charged $10-$15 (the price of a magazine) for it, you could have an audience.