+1 on the PB and apples or celery is good too as well as granola bars. I have a disdain for soy, starting with ultra processed food and kids don't mix.
While one of our head coaches preferred our gymnasts didn't have dairy products as a snack during gym, before it might be ok, especially if they were lactose tolerant. Ingesting dairy tends to require a lot of blood to help process it in the stomach so it would have to depend how much time it was ingested before the workout.
Hard boiled eggs are another excellent idea or most fruit, bananas or carrots I'm big on.
However, I've heard the way peanut butter is processed makes it not necessarily a high quality food. Something about legumes and mold. I think it was referenced in the China diet study, but I have opinions about that as well.