General Knoppix support for those who've read the FAQ at the Wiki
1U Supermicro Server 10 Bay 2x Intel Xeon 3.3Ghz 8C 128GB RAM 480GB SSD 2x 10GBE
$273.00
Supermicro 1U X11DPU 2x Xeon Gold 6132 2.6GHz / 128gb / 10x 2.5 Trays / 2x 750w
$649.99
SuperMicro Server 505-2 Intel Atom 2.4GHz 8GB RAM SYS-5018A-FTN4 1U Rackmount
$202.49
SuperMicro CSE-836 16LFF Server X9SCL+-F Xeon E3-1220V2 3.10GHz CPU 8GB RAM
$169.99
HPE ProLiant MicroServer Gen10 Plus v2 Ultra Micro Tower Server - 1 x Intel Xeon
$846.48
HP HPE Microserver Gen 7 8 9 iLO 2/3/4/5Advanced License Lifetime Key| FAST SHIP
$10.00
Supermicro 6028U X10DRU-i+ 2x LGA2011v3 Xeon E5-2600v3/v4 2U Server CTO
$199.99
Supermicro CSE-825-7 X10DRW-i 2 Xeon E5-2667v4 3.2GHz SAS3 2U One Power Supply
$209.75
1U BareMetal pfsense opnsense Router Firewall DNS Server 6x 10GB Ethernet Ports
$149.00
1U 20" Short Depth Server Firewall PFSense X11SSH-F Xeon 3.5Ghz 32GB RAM NVME
$247.00