That Intergraph monitor.. that's off a Clipper UNIX box. Probably a 2xxx series.
I used to run those on some 2400's and a 6800 with CLIX. Dead tech sadly, though it was a lovely UNIX and the Clipper RISC (C[1,2,3,4]00's) processors for the day were pretty nice. Quite unobtanium these days.
Monitors were easy to get working off VGA if the card supplied SOG signals correctly.