I have built quite a few custom rigs over the years and my go to site for researching parts has been https://pcpartpicker.com/.
PCpartspicker will let you research component's for your build, check on compatibility, and show you where to get the best pricing among mainstream vendors.
I put this parts list together for an Unraid build. I know the CPU is overkill but I have one laying around.
https://pcpartpicker.com/list/3JjBqm