I got nothing. Going to AMD Ryzen, there aren't many options. Most of the volume is Intel (I am master of the obvious).
I'd go with a 2x16GB memory config. I don't think you'll see much performance difference going with a 4x8 and it'll leave you the ability to go to 64 later without having to replace all of the DIMMs. The Ryzen 5 will likely be the limiting factor, not the RAM.