Disclaimer: I do not condone copyright infringement.
Unfortunately, you cannot extract all of the presets in one go. You will need to copy and paste each preset to a new soundfont file, and save all of the soundfonts.
open the SF2 in Polyphone, then create a new soundfont and drag every Preset you like from the Preset-folder of the soundfont to the Preset-folder of your new creation.
regards bottrop
