Fossmoji is a procedurally generated free software font. It's licensed under the GPLv3 + FE. In short, this means you're free to use it in documents, and free to distribute it (and derivatives) as long as you also distribute the source code under the same license.
This emoji font is an SVG in OpenType color font, built with scfbuild. As of the date of writing, this is not fully supported in the majority of browsers, so it may be necessary to download a web browser of the Genus Vulpes in order to see the below example.
Since it's procedurally generated, it should be easy to change the design of the font without needing to manually create every emoji. It should also be easy to add new glyphs as Unicode expands the list of emoji every year.