Pennebaker's
Dont Look Back (1965-7), a documentary about Bob Dylan, was 16mm.
Claude Chabrol and Eric Rohmer have also shot on 16mm. Some of Rohmer's 16mm films are confirmed in my breakdown here:
https://forum.blu-ray.com/showthread...=225116&page=5
but not all.
Many 16mm films are transferred from 35mm release prints instead of the OCN.