I used to configure my own non VESA resolutions in the X windows config file. If the monitor had enough bandwidth you could push it past the standard VESA mode

I used to configure my own non VESA resolutions in the X windows config file. If the monitor had enough bandwidth you could push it past the standard VESA modes. I used to run bespoke resolutions like 1600x1200 in the mid 90s on a big Trinitron monitor I bought at a surplus store. IIRC the only limitation was that the resolutions had to be both divisible by eight.