It took until fall season 2020 but...
An official Sonic Face Mask / Cover finally appears. No doubt this is by any random company that could simply buy up enough official Sonic printed fabric fast enough to throw these together on one of the numerous existing 'youth mask' patterns, but, oh well because the bootleggers were having a field day with their phony fabric.
This is a 3 pack of masks, for about 12.99 at Game Stop. They're in the simplest of label-bag packaging so as to bring them to market faster. The fabric is blue, with classic Sonic faces scattered around, as well as rings. There's normal, 'steamin'-Sonic', aggrivated, forward-winking and probably profile faces.
They're a fine, normal and solid enough design for something with the classic type look. Hopefully more variety of Sonic fabric will become available/more mask styles could appear for all sizes of faces.