The portable one is this: https://smile.amazon.com/dp/B07JPJ5795/ref=cm_sw_r_cp_apa_i_ZXrkCbFH8GFVA

I had a plug in one that was my mom's I think from the 80s or so, but it finally died. I can't even remember a brand name on it lol.

I don't see why a pregnancy pillow wouldn't work, it might even be better to give her more of a surround cushion 🤷‍♀️