For my next project I'm planning to build a box with multiple video cards to passthrough to different VMs. I'd like an XP era machine, 98se...maybe a dos but that's a big unknown. I'd probably also include Windows 7 VM to play later 2000s games. This project would save some space but its more about the journey, I acknowledge its an over-complicated idea.

I plan to built this off of an existing biostar z77 socket 1155 motherboard that has PCI and PCI-e. It used to be my unraid server, so I know it works with passthrough. It has a i5-3470.

That said, I'm looking for some advice on the right video cards to pick for the eras.
I currently have these cards working in passthrough, at least to a very basic level:
Geforce PCX5750 (fan is dead, DOES work in passthrough but need to stability test and fix)
Geforce MX4000 PCI
Canopus Pure3d voodoo1
Cirrus Logic 5446 PCI

I was thinking of pairing the pure3d with the cirrus logic with the voodoo and having it do 9x. Then if the PCX5750 doesn't work for the XP VM either using the MX4000 or maybe picking up a PCI FX 5200. Then something more powerful for later games in a PCI-e variant. But maybe there are better pairings for compatibility?

I can't use AGP, there aren't any boards that work with passthrough that exist AFAIK.

Getting USB working in 98se with passthrough will be a challenge, let alone DOS. My passthrough USB cards are all USB 3.0, which works with XP but 98se is just a bridge to far.