In a comment to my answer here, @Οurous pointed me to an important find I had missed. The European Modern fonts by Y&Y were originally a commercial add-on for Y&Y TeX, and are missing from the yandytex packages on CTAN. They are superior in some ways to the
cm-super fonts that are currently the default for LaTeX with the Cork encoding, and are closely related to the “Blue Sky” fonts (from Y&Y in the ’90s) that are the default when using the original OT1 encoding. However, the European Modern files are not available from CTAN, or in any distribution I am aware of.
Of note, the support files to use European Modern are on CTAN as the
psnfssx-em package, last updated in 2001. These do not distribute the fonts themselves, but only provide support files if you have copies of the fonts Y&Y used to sell in the 1990s.
However, a version of the fonts originally shipped on four diskettes was donated to TUG and is available freely for download on GitHub, with a copyright statement that says “Copyright 2007 TeX Users Group,” and that ETA: The original release was on Google Code, and the GitHub link is to a mirror.
Blue Sky, Y&Y, and the AMS released the AMS and Computer Modern fonts long ago under free software terms. To whatever extent that Y&Y had any remaining proprietary improvements in the fonts as they are included here, they have been assigned to TUG, and TUG hereby releases them as free software, under the one-sentence all-permissive license (to avoid license compatibility problems):
You may freely use, modify and/or distribute the material here.
Any complete fonts given here which have not previously been released (I'm not sure if there are any) are also hereby released under that all-permissive license.
Is there any reason TUG could not make the European Modern fonts, which they claimed to own in 2007, freely available today? Is the situation that anyone could have bundled them into a package at any time since 2007, but no one ever did?