I do not normally work with Yamaha stuff but bought a mixer as I wanted some parts from that for another job so thought will list these here

They also seem to be the same or similar to some of the Behringer knobs

18.75mm high 11.4mm wide two shot mould 6mm d shaft

The small push buttons are about 9mm high 6.86x5.35mm and designed for a 3mm shaft

I also have some clear ones marked "on"

price for 1