Etcetera Type Co

Big stuff from a little company based out of upstate New York. The founder has been creating open source fonts since 2009.etc.supply
ETC recently released a free variable font (though not open source) in addition to a catalog of paid typefaces, and they are all variable. Tyler contributes regularly to The League of Moveable type, one of the first open source foundries. His most recent work there was League Spartan Variable.