Roland (yes the musical instrument people) used to make a range of plotters for Macs in the 1990s. They were connected via the serial port and were moderately popular at the time.

x2 re the HP designjet / paintjet range.

Weirdest plotter I came across on a Mac had a small cutter instead of a pen and cut a stencil from a rubber sheet. It had custom software and was used for making tombstones! The rubber stencil was placed over the stone and sandblasted so the rock would be removed where letters were cut out of the rubber. "here lies..."