There is some nuance here.

It is legal to share chord progressions. Most of the time, that's a BIAB file type of SGU. It is not legal, without permission or the payment of royalties, to share these fakebook songs with melodies as an .MGU file. Thus you see all kinds of variations out there.

You might be surprised to know that more than a few of the PG Music demo songs (which are themselves copyrighted) use the chord changes of jazz standards. To my knowledge there isn't a list cross-referencing these, although it has been suggested a few times over the decades.

And of course, even if you find some .SGU files of jazz standards, the quality of the work can vary. Are they using the right chords and upper extensions? Shots and holds and anticipations in the right place? Plus, there is a lot of disagreement if the chords in those earlier Real Books were even correct.

My recommendation is to look at the nortonmusic.com site. Bob 'Notes' Norton has made, legally, BIAB disks that are great quality. It's worth paying for.

BIAB 2025 Win Audiophile. Software: Studio One 7 Pro, Swam horns, Acoustica-7, Notion 6, Song Master Pro, Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus 192 & Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors.