Isla Fischer / Amy Adams
Margot Robbie / Samara Weaving / Jamie Pressley
Justin Long / Ezra Miller
Not to mention all of the token/stereotype characters where it hardly matters who the actor is at all. Need to fill the funny fat lady trope? If Rebel Wilson wasn't available, maybe they can get Melissa McCarthy.
The voice from Her isn't even the first voice I'd think of for a female computer voice. That trope has been around for decades. I'm sure OpenAI just wanted SJ specifically because she's currently one of the most popular celebrities in the world.