There are quite a few that are free for all, but most of them come with some restrictions. I tried to get a count of them[1] and got these numbers:

General Public Release - 132

U.S. Release Only - 210

U.S. Government Purpose Release - 139

U.S. and Foreign Release - 38

[1] These were counted by looking for strings in the PDF catalog. There are definitely some duplicates.

   wget https://software.nasa.gov/sites/default/files/NASA_Software_Catalog_2023-24.pdf
   gs -sDEVICE=txtwrite -o a.txt NASA_Software_Catalog_2023-24.pdf
   grep -F "General Public Release" a.txt | wc -l
   grep -F "U.S. Release Only" a.txt | wc -l
   grep -F "U.S. Government Purpose Release" a.txt | wc -l
   grep -F "U.S. and Foreign Release" a.txt | wc -l