Rancilio
Rancilio doesn't market on plastic, but the Silvia's heated brew path is brass: a brass boiler feeds a commercial brass group head, and the portafilter is chrome-plated brass. Brew water contacts only brass and steel. The plastic is the pour-over cold-water reservoir and the (non-wetted) portafilter handle.
How clear are their specs?
Rancilio specs the brass boiler and commercial group head; the group gasket compound isn't named on the official page, and the plastic reservoir is visible.
