The <ulink url="https://github.com/liberationfonts/"> Liberation fonts</ulink> provide libre substitutes for Arial, Courier New, and Times New Roman. <application>Fontconfig</application> will use them as substitutes for those fonts, and also for the similar Helvetica, Courier, Times Roman although for these latter it can prefer a different font (see the examples in the 'Substitutes' PDFs at <ulink url="http://zarniwhoop.uk/files/PDF-substitutes/"> zarniwhoop.uk).</ulink>