The png files are included with the PixelFont asset. https://henrysoftware.itch.io/pixel-fonts
The png files can be extracted from other assets with Texture.EncodeToPNG() https://gist.github.com/rakkarage/167d64e7dc8ebdcb6857b40c969edbf3 if you use Unity.
If you can not or will not get them any other way you can email me (rakkarage gmail com) from an address that has purchased a package with fonts included and I will email you the pngs back.
Thank you.