https://www.amazon.com/CAMVATE-Release-Manfrotto-Standard-Accessory/dp/B06X3VSNF3/ref=sr_1_5?dchild=1&keywords=camvate+baseplate&qid=1601334394&sr=8-5

https://www.amazon.com/NICEYRIG-Shoulder-Support-Baseplate-Railblock/dp/B06XKQJYX2/ref=sr_1_22?dchild=1&keywords=niceyrig+rail+block&qid=1601334541&sr=8-22

Doesn’t have to be this exact one, just an example: https://www.amazon.com/CAMVATE-Release-Manfrotto-Standard-Accessory/dp/B06X3VSNF3/ref=sr_1_21

But if you get a base clamp like that you can just attach it to any non-Manfrotto plate to make it compatible with what you want.