Portable monitors..

[PA-WOODCHUCK]

I have surface book 2, does it support portable monitor through USB port?

 

[GreyFox7]

SB 2 Specs ... Surface Book 2 specs, features, and tips - SurfaceTip

• 1 x USB Type-C 3.1 Gen 1
  Supports Power Delivery and DisplayPort.

so yeah it supports DisplayPort over USB-C