Zen+ (Pinnacle Ridge) CPU is indeed working on some B550 boards - here is my R5 2600 on TUF GAMING B550-PLUS : r/Amd
AMD's Pinnacle Ridge Zen+ 12 nm CPUs to Launch on February 2018 | TechPowerUp
Amazon.com: ABYS Pinnacle Prebuilt Gaming PC (Intel Quad-Cord CPU Up to 3.6GHz, 16GB RAM, Nvidia 1660 Super 6GB GDDR Graphics Card, 1TB SSD, HDMI, DP, Multi Monitors Supported, Windows 10 Gamer Desktop
AMD rumored to launch Ryzen 2 on 12nm in February 2018
Amazon.com: ABYS Pinnacle Prebuilt Gaming PC (Intel Quad-Cord CPU Up to 3.6GHz, 16GB RAM, Nvidia 1660 Super 6GB GDDR Graphics Card, 1TB SSD, HDMI, DP, Multi Monitors Supported, Windows 10 Gamer Desktop
AMD Ryzen 2000 Desktop CPUs Specs, Prices and Performance Leaked