Having been on bedrest with two previous pregnancies, this is a question that I can answer! My list is almost entirely service related instead of physical gifts because those are the things that, IMO, a woman on bedrest really needs.
A nice long visit! I'm pretty introverted, but I was starving for face-to-face contact with other adults. If I end up on bedrest again, this would be the very best gift anyone could give me.
Someone to take a list of books, or authors I like, and make a library run for me on a weekly basis.
A Netflix subscription. (Assuming she doesn't already have one.)
Meals, so DH doesn't have to do all of the cooking and we could avoid excessive take-out.
Cleaning help.