The above statement is probably true on maybe 97% of the songs you’ll ever encounter, as it’s always possible that there is something new that will come around the pike that will go outside of the harmonic situations that these songs present. (*) denotes not in the original Real Book.)
Attached as a PDF is a list of the 30 songs that I have played from the Real Book that taught me what I needed to know to play pretty much everything else I have encountered since then. I have also included the reason why I included each song, with a short explanation of terms below that. I have also tried not to include any really obscure rarely played tunes, so that you are learning songs that will get called on gigs as well.
Please note that there are no major or minor straight blues form tunes here – make sure you learn those forms before you start any of these tunes.
For more great improvisation learning, check out some of the below:
The Minor 3rd Trick (ii/V/i soloing)