[flembat]

It was a long time ago, but I vaguely recall using a standard graphics extension on CP/M. It had a lot of gray scale fill patterns and could draw geometric shapes on a bitmapped display. I was using a z80 system on green monochrome display, and enjoyed watching the graphics slowly plotted onto the display.

[NikkiA]

That sounds a lot like the PCW8256 or 8512 and locomotive's CP/M Plus and the few dozen apps/games that supported it.

If so it wasn't a 'standard' per se; but it was common across the Spectrum +3, the PCWs, and the Amstrad 664/6128.

There may have also been some software to enable such software to also work on the Tatung Einstein and the Enterprise Flan (which didn't 'technically' run CP/M at all, but IS-DOS was compatible enough to run most CP/M software).