Well, I'm at work right now so I don't remember my whole collection atm. For sure though I don't have a 6100. This is what I have:

Apple IIGS

Macintosh SE

Performa 450

Performa 631CD

LC 575

Power Macintosh 6500 W/ Sonnet G3 upgrade

Power Macintosh 7600 (or was it 7200...)

Power Macintosh 8600 (or was it 8500...)

Power Macintosh G3

Power Macintosh G3 B&W

Power Macintosh G5

And that's it for my desktop models. Any chance your card could fit in one of those?