You can walk through the queue of Forbidden Journey and not go on the ride. You can watch the Frog Choir, Celestina Warbeck, or the Tales of Beedle the Bard, meet a Goblin at Gringotts, see the Ollivander's show, or get a wand and do spells to your heart's content. You can ride the Hogwarts Express both ways.
In the rest of the parks there's the Seuss rides (I think a pregnant person could ride all of them), ET, the Hollywood Horror Makeup show and other shows, greet characters, visit the Dinosaur Discovery Center and meet a raptor, squirt people on the Popeye water rides, relax waterside with a frosty drink, get your photo taken with Jaws, and watch parades!