Yes, originally CGA and MDA at the same time. Hercules was a non-IBM standard, based on MDA. Hercules has 64k of memory, where 32k is in the area of MDA, and the second 32k overlaps with the CGA area. You could disable the second 32k when you had a CGA card in your system.
EGA and VGA were also made backwards compatible, and could co-exist with an MDA or Hercules card.
The demo Stars by NoooN (https://www.pouet.net/prod.php?which=301) has an easter egg for a combination of VGA and MDA/Hercules: on the monochrome screen, a Snake game appears, which can be played via keyboard while the demo is running.
The demo Stars by NoooN (https://www.pouet.net/prod.php?which=301) has an easter egg for a combination of VGA and MDA/Hercules: on the monochrome screen, a Snake game appears, which can be played via keyboard while the demo is running.