28 Cores in Mini-ITX: ASRock Rack EPC621D4I-2M Motherboard for Xeon Scalable
Amazon.com: AsRock Rack E3C256D4I-2T Mini-ITX Server Motherboard Single Socket H5 (LGA1200) Intel Xeon E-2300 and 10th Gen Pentium Series C256 Dual 10GbE : Electronics
Server-grade mini PCs: ASRock reveals "Deep mini-ITX" motherboards with AMD EPYC Rome CPU support - NotebookCheck.net News
SUPERMICRO X10SDV-TLN4F Mini ITX Server Motherboard Xeon D D-1541 10GB Quad LAN | eBay
AsRock Rack X570D4I-2T Mini-ITX Server Motherboard AM4 PGA 1331 X570 AMD Ryzen 3rd Generation Series Processors - Walmart.com
AsRock Rack B550D4ID-2L2T Deep mini-ITX Server Motherboard AMD Ryzen 5000 Series AM4 (PGA 1331) B550 Dual 1GbE+10GbE - Walmart.com