There’s also this: Magnetic Go Board with Single Convex Magnetic Plastic Stones Game Set https://www.amazon.com/dp/B000JHSORK/ref=cm_sw_r_cp_api_i_DGZ5AbWCJDCYE

I have this and it’s actually quite nice and compact. It’s good for playing somewhere where tablespace is limited. We use them at a group I meet with that plays at a bar.