General Knoppix support for those who've read the FAQ at the Wiki
HP ProLiant ML350 Gen 9 Server 64GB RAM 2.4GHz Xeon 12-Core E5-2667 v3
$300.00
1U Supermicro Server 10 Bay 2x Intel Xeon 3.3Ghz 8C 128GB RAM 480GB SSD 2x 10GBE
$273.00
New Gigabyte 10 bay SFF Server 2x Xeon Gold 6130 Total 36 Core 64GB DDR4 3x PCIe
$699.00
HP ProLiant DL360 G9 Server 2x Xeon E5-2697 V3 28 Cores P440ar 128GB DDR4 1x SSD
$249.99
Dell PowerEdge R620 Server - 256GB RAM, 2x8cCPU, 120Gb SSD/3x900Gb SAS, Proxmox
$320.00
R630 DELL 8 x 2.5'' POWEREDGE 2X E5-2680V4 32GB RAM IDRAC ENT & NDC 2X 495W PSU
$169.95
SuperMicro Server 505-2 Intel Atom 2.4GHz 8GB RAM SYS-5018A-FTN4 1U Rackmount
$202.49
CEOhack 1U X9DRW-3TF+ 4 Bay Server 64GB DDR3 1x E5-2667 V2 3.30GHz 8C 1x 1TB HDD
$119.00
Dell PowerEdge R620 Server 2x E5-2660 v2 2.2GHz 20 Cores 256GB RAM 1x 480GB SSD
$139.99
1U 20" Short Depth Server Firewall PFSense X11SSH-F Xeon 3.5Ghz 32GB RAM NVME
$247.00