Hercules graphics drivers?

Its provision of an MDA compatible high quality text mode in combination with a (for its time) high resolution graphics mode (as well as aggressive pricing) made the Hercules card extraordinarily popular in the early days of the PC. The existence of CGA emulation drivers/TSRs, which allowed Hercules users to run programs written for the CGA card's standard graphics modes (albeit only in monochrome, without actual colour), may also have been a contributing factor to its success, especially so because programming for the Hercules card's native graphics mode was somewhat hindered by the fact that there was neither any BIOS support nor standardization from IBM — after all, the HGC was a competing technology!