You can get 3d printing filament with a mixture of like 80% metal powder and the rest PLA that can be sintered, ie heated to be like 1200-1300C, to end up with a metal object that's essentialy printed on a regular 3d printer. Maybe glass powder could also just be mixed in melted PLA and then extruded to get a filament that could be used in regular 3d printers and then sintered to get a glass object.