3D printed 1911: https://en.wikipedia.org/wiki/Solid_Concepts_1911_DMLS
Let me ask you this - what part of a toaster oven do you think could *not* be made by 3D printing?
Paneling and door? Metal slabs, easily printed.
Heating element? You can print those, even on micro and nano scale. https://3dprint.com/135079/graphene-3d-print-heating-elements/
Timer? People make far more complex clocks than is needed for the timer on a toaster oven. https://3dprint.com/109956/zmorph-hybrid-clock/
The switch? Simply printed knife switch if you want to go primitive, metal printed parts mounted on a plastic printed base.
So, what part do you think can’t be printed?