This was just shared on Facebook, and I want to forward it here since - while not related to music engraving directly - it may be useful to people on this list.
https://bit.ly/2qouMtH?fbclid=IwAR2kWD64268-n2cqKagJ5AxVntbxRsPFN48q61aZ8ORwB6s54vGmHeWJNZU This points to an archive on Dropbox, containing the SIL-licenced font family "Glyph3 /Synth. A font designed to notate faders, knobs, wheels, signals and other synthesizer related stuff." I don't know whether I'll have any use for it but it looks cool. Best Urs