U210 would be a good option. Also LTC Stealth (28720) or Tencate CR2000SA or CR6400SA are good options.
LTC, Hesco, and Tencate are probably the "big 3" mfgs. Several vendors sell plates that are rebranded version of them. The STOP BZ, Velocity BZ and Tencate 6400SA are essentially the same plate. The spec is almost the same as the U210. The biggest difference is in the testing. Even the Paraclete Speed Plate Plus is really a CR2000SA.
AT Armor would be a good vendor. I'd also recommend checking out Battalion Defense.