Growing up grape jelly was the only jelly I knew of in a PBJ. We had grape vines in the back yard and my mother would make grape jelly. I didn’t know how good I had it! It wasn’t until I was in high school when I went to a friend’s house and his mother made us PBJs with home-made strawberry preserves- mind blown. Since then I’ve branched out into all kinds of jellies/jams/preserves to accompany my peanut butter but for me the platonic ideal will always be grape jelly.