Definitely folding on Linux here, but I doubt that any of the GPUs I have would be useful. My purchasing criteria for a videocard for the longest time has always been that it has a digital output for an LCD monitor (none of that D/A => A/D double conversion) with a clear high resolution 2D picture for a simple X-windows desktop.
The only reason I have any videocards with 3D capabilities is that those are the ones that end up on the clearance sales a year or two after they were introduced.
A quick look at some of the stuff I have:
Number Nine, Matrox not supported at all
Rage 128, Rage Fury Pro, Radeon 7000, Radeon 7500 listed in GPUs.txt but not supported by F@H
Radeon HD 6450 looks like it might work
NV1, Quadro FX 5500, Quadro NVS 285 listed in GPUs.txt but not supported by F@H
GeForce 210 looks like it might work
Those might work cards are pretty low-end and are probably not going to perform very well.--
Got some spare cpu cycles ? Join Team Helix or Team Starfire!