AMD Ryzen compatible RAM Memory seems to list RAM Speeds up to 3200Mhz.
To get RAM Speeds above 3200Mhz you need to go the the Motherboard's QVL List for the 3000 Series Matisse processor list or go to the RAM Manufacturer site and see if the RAM is compatible with your motherboard and processor.
I recently upgraded my computer to a Ryzen 7 3700x Asus Motherboard. I purchased a set of G-Skill Trident-Z Neo RGB (2x16GB) 3600Mhz CL16 RAM and it works perfectly after I used Asus BIOS to Overclock to 3600Mhz.
The Trident-Z Neo are made to be compatible with Ryzen Processors. But there are other RAM just as good from other RAM Manufacturers.
3600Mhz is the sweet spot for the Matisse processors in which the processor has the best performance.
Make sure the RAM you purchase is compatible with the amount of DIMM Slots that you are going to populate and can be Overclocked or not. All info listed on the QVL List.