How's this for a collection, do you have better, or worse:

1. i7-3770 16GB, GTX1060 (operational) - Win10
2. X4 965 8GB, GTX 750 Ti (operational) - Win10
3. C2D E8500 6GB, GT730 (open test) - Win10
4. C2D Laptop 4GB (under upgrade from Celeron) - fairly recent buy - to be Win10
5. P4 640 2GB, HD5670 - was XP, testing Win10
6. Atom N450 Netbook, 2GB - (operational) Win10
7. Dell P4 768MB RDRAM GF2MX awaiting PSU and Radeon 9800Pro - WinXP on
8. Athlon XP GF2MX awaiting GF4 Ti4200 - WinXP on, I think
9. Athlon Thunderbird 1000 384MB, GF4MX Win98 on, bad case of WinRot
10. P233MX ? ? - abandoned as was - may be 98, may be DOS/3.1
11. P75 (possible upgrades), 32MB, onboard S3 Trio - Win95 on, I think
12. 486 DX4 100 - this was Win98, but will probably make DOS

This is my dirty dozen... #3 was intended to be a reserve system before #2 was displaced by #1. Some are my own previous setups, others were hand me downs, and landing a couple of nice AGP cards has me itching to revitalize the best of my AGP boxes (neither of which are my own old system, that's the Thunderbird).... probably in XP or XP/98 dual boot.
And I'm still kicking myself for not grabbing a Voodoo (3 I think) for a fiver all those years back, when I was on Win 98 and the Voodoo was in its dying era.