Per the homepage, the TeX Gyre project provides:
[…] an extensive remake and extension of the freely available 35 base PostScript fonts distributed with Ghostscript ver. 4.00. The important aspect of the project is providing not only the support for TeX but also the cross-platform OpenType format of the fonts.
The project includes the following font families (in alphabetical order):
The font families included in this repo are linked above; all families can be downloaded directly from the project website. The TeX Gyre project also includes math fonts corresponding to several of the font families above.
The TeX Gyre project states (links added for convenience) describes their license as follows:
The TeX Gyre fonts are licensed under the GUST Font License (GFL), which is a free license, legally equivalent to the LaTeX Project Public License (LPPL), version 1.3c or later.
Additionally, the project provides some history behind the licensing:
One should however note that licensing of the TeX Gyre fonts under the GFL has become feasible only after the URW++ company allowed the distribution of the 35 base Postscript fonts as shipped with GhostScript 4.00 to be also governed by the LPPL. This happened on the 22nd June 2009, with the personal involvement of Dr. Peter Rosenfeld, URW++’s manging director.
as well as usage guidance and a request from the project:
The freedoms granted by GFL include the free use of the fonts for whatever purpose you wish. You can also take the fonts and modify them for your own use or redistribution, but to avoid confusion in such a case you are requested to change the name(s) of the font(s) and comprising files—please follow the guidance of the license.
Note: URW Type Foundry, formerly known as URW++, was acquired by Monotype in May 2020.