GNU FreeFont (FreeSans, FreeSansBold) is released under the GPLv3

wqyMicroHei is released under the GPLv3 with font embedding exception and Apache-2.0 licenses
    By Qianqian Fang and The WenQuanYi Project Contributors
    Copyright (C) 2008-2009  The WenQuanYi Project Board of Trustees
    Copyright (C) 2007  Google Corporation

Noto Naskh Arabic UI is released under Apache-2.0 license

Ubuntu font is released under the ubuntu font license (http://font.ubuntu.com/licence/)

SigmarOne is released under the SIL open font license 1.1 ( https://www.google.com/fonts/specimen/Sigmar+One )