Ok so in the driver .INF of the Win9x Catalyst 6.2 package that is supposedly only for cards of 9000 series and older, we have:
"RADEON X800" = R420_ENU, PCI\VEN_1002&DEV_4A4B&SUBSYS_00021002
"RADEON X800 PRO" = R420_ENU, PCI\VEN_1002&DEV_4A49&SUBSYS_00021002
"RADEON X800 PRO Secondary" = R420_ENU, PCI\VEN_1002&DEV_4A69&SUBSYS_00031002
"RADEON X800 Secondary" = R420_ENU, PCI\VEN_1002&DEV_4A6B&SUBSYS_00031002
"RADEON X800 XT Platinum Edition" = R420_ENU, PCI\VEN_1002&DEV_4A50&SUBSYS_00021002
"RADEON X800 XT Platinum Edition Secondary" = R420_ENU, PCI\VEN_1002&DEV_4A70&SUBSYS_00031002
"ASUS Extreme AX300SE/T 128MB" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_002A1043
"ASUS Extreme AX300SE/T 128MB - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_002B1043
"ASUS Extreme AX600XT-TD 128M" = RV380_ENU, PCI\VEN_1002&DEV_3E50&SUBSYS_001E1043
"ASUS Extreme AX600XT-TD 128M - Secondary" = RV380_ENU, PCI\VEN_1002&DEV_3E70&SUBSYS_001F1043
"Gigabyte RADEON X300 128MB" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_21021458
"Gigabyte RADEON X300 128MB - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_21031458
"Gigabyte RADEON X300 SE 128MB" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_21021458
"Gigabyte RADEON X300 SE 128MB - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_21031458
"GIGABYTE RADEON X600 PRO 128MB - Secondary" = RV380_ENU, PCI\VEN_1002&DEV_3E70&SUBSYS_21011458
"GIGABYTE RADEON X600XT 128M Secondary" = RV380_ENU, PCI\VEN_1002&DEV_3E70&SUBSYS_21011458
"GIGABYTE RADEON X600XT 128MB" = RV380_ENU, PCI\VEN_1002&DEV_3E50&SUBSYS_21001458
"ABIT RADEON X600XT 128M" = RV380_ENU, PCI\VEN_1002&DEV_3E50&SUBSYS_0001147B
"ABIT RADEON X600XT 128M Secondary" = RV380_ENU, PCI\VEN_1002&DEV_3E70&SUBSYS_0000147B
"C.P. Technologies Inc. RADEON X300SE" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_2089148C
"C.P. Technologies Inc. RADEON X600 PRO 256MB" = RV370_ENU, PCI\VEN_1002&DEV_5B62&SUBSYS_2083148C
"C.P. Technologies Inc. RADEON X600 PRO 256MB - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B72&SUBSYS_2082148C
"RADEON X300 Series Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_2088148C
"SAPPHIRE RADEON X300SE 128MB" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_0500174B
"SAPPHIRE RADEON X300SE 128MB - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_0501174B
"SAPPHIRE RADEON X300SE 128MB PCI-E" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_0440174B
"SAPPHIRE RADEON X300SE 128MB PCI-E - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_0441174B
"Sapphire RADEON X600 PRO 256MB" = RV370_ENU, PCI\VEN_1002&DEV_5B62&SUBSYS_0450174B
"Sapphire RADEON X600 PRO 256MB Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B72&SUBSYS_0451174B
"GeCube RADEON X300 PCIE 128M" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_060018BC
"GeCube RADEON X300 PCIE 128M Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_060118BC
"GeCube RADEON X300SE 128M" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_040018BC
"GeCube RADEON X300SE 128M Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_040118BC
"Celestica "Gold Edition" RADEON X300" = RV370_ENU, PCI\VEN_1002&DEV_5B60&SUBSYS_002E18D4
"Celestica "Gold Edition" RADEON X300 - Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B70&SUBSYS_002F18D4
"Celestica "Gold Edition" RADEON X600 Series 128MB" = RV380_ENU, PCI\VEN_1002&DEV_3E50&SUBSYS_002A18D4
"Celestica "Gold Edition" RADEON X600 Series 128MB Secondary" = RV380_ENU, PCI\VEN_1002&DEV_3E70&SUBSYS_002B18D4
"RADEON X300 Series" = RV370_ENU, PCI\VEN_1002&DEV_5B60
"RADEON X300 Series Secondary " = RV370_ENU, PCI\VEN_1002&DEV_5B70
"RADEON X550" = RV370_ENU, PCI\VEN_1002&DEV_5B63
"RADEON X550 Secondary" = RV370_ENU, PCI\VEN_1002&DEV_5B73
"RADEON X600 Series" = RV380_ENU, PCI\VEN_1002&DEV_3E50
"RADEON X600 Series " = RV370_ENU, PCI\VEN_1002&DEV_5B62
"RADEON X600 Series Secondary" = RV380_ENU, PCI\VEN_1002&DEV_3E70
"RADEON X600 Series Secondary " = RV370_ENU, PCI\VEN_1002&DEV_5B72
"RADEON X800 PRO/GTO" = R420_ENU, PCI\VEN_1002&DEV_4A49
"RADEON X800 PRO/GTO Secondary" = R420_ENU, PCI\VEN_1002&DEV_4A69
"RADEON X800 Series " = R420_ENU, PCI\VEN_1002&DEV_4A4B
"RADEON X800 Series " = R420_ENU, PCI\VEN_1002&DEV_4A4A
"RADEON X800 Series Secondary" = R420_ENU, PCI\VEN_1002&DEV_4A6A
"RADEON X800 Series Secondary " = R420_ENU, PCI\VEN_1002&DEV_4A6B
"RADEON X800 XT Platinum Edition " = R420_ENU, PCI\VEN_1002&DEV_4A50
"RADEON X800 XT Platinum Edition Secondary " = R420_ENU, PCI\VEN_1002&DEV_4A70
X700 and X850 are absent but this looks rather comprehensive.