In addition to those I'm adding clion-eap, intellij-idea-ue-eap, pycharm-pro-eap, firefox-beta, opera-developer, vivaldi, slimjet, ttf-opificio and yaourt. Upstream gfxboot is free [1] but the Anteregos package doesn't look like it's being built from sources,[2] nor is terminix, nor their icecat (please correct me if I'm mistaken). icecat and octopi are already being taken care of so they don't need to be blacklisted. Upstream terminix claims to need dmd in order to build, so it belongs straight to the blacklist.

I don't know where that grub-zfs package is coming from, I don't see a corresponding PKGBUILD.

I couldn't retrieve the sources used by libreoffice-installer, pacmanxg4 (both PKGBUILDs invoke the same dead host http://almin-soft.fsay.net), pam_encfs (google code broke this PKGBUILD and it hasn't been fixed) and numix-icon-theme-square.

ttf-google-fonts contains fonts licensed under the Ubuntu Font License (a SIL Open Font License 1.1 derivative). It looks free to me and so does the package as a whole, but the FSF hasn't commented on this specific license.

The following packages could be free to the best of my research (some of them we already package in our repos):

ckbcomp compton copyq corebird divehi-fonts dummy-package dummy-package-git econnman feedreader gcab gnome-shell-extension-dash-to-dock gnome-shell-extension-panel-osd gnome-shell-extension-status-menu-buttons gnome-shell-extension-topicons grub2-editor gtk-theme-arc gtk-theme-paper html2text kde-servicemenus-rootactions kdesudo kfaenza-icon-theme kmozillahelper libechonest-qt5 liblastfm-qt5 light-locker-settings mate-mint-menu n1 numix-frost-themes numix-icon-theme openbox-menu package-query pamac pamac-dev paranoid plank-theme-numix plymouth pm2ml powerpill profile-sync-daemon pycharm-pro-eap python-bugsnag python-dbusdecorator python-efl python-parted python3-xcpf rage remendo ruby-sass scudcloud spl spl-utils ssx tomahawk ttf-aboriginal-sans ttf-myanmar3 ttf-opensans vte-notification-common vte3-notification waldorf-ui-theme xinput_calibrator zfs zfs-utils zuki-themes zukitwo-theme-openbox
(It looks like the n1 PKGBUILD has incorrect license metadata; it should be GPL3 not MIT. That may merit writing a report to the AUR and Ateregos maintainers)

I didn't check their dependencies and optional dependencies; I'm not taking branding issues into consideration either as per your petition.
Would you like to comment before I push those changes to the blacklist?

[1]: https://github.com/openSUSE/gfxboot
[2]: https://github.com/Antergos/antergos-packages/tree/master/gfxboot