It’s perfectly possible that there will be giants, in BA or any of the AU’s!
The great thing about Supernatural is the possibilities are endless for different types of interaction with gt. The show has never had actual giants on it, but it has had a golem (who proceeded to toss Dean about twenty feet through the air), and it has had fairies (the closest we’ve gotten to a gt episode with little gnomes running around making watches aah I love that episode so much).
If you ever have a chance, the show is a ton of fun, but otherwise, the stories will keep coming here, and we do our best so that you never need to see an episode to get into the story.
I’m gonna keep wishing for more gt episodes in the future, but until then the stories shall continue! And if you’re ever craving some giant supernatural gt in the meantime, check these out (slightly more tied into the show than mine are, but I read them all myself before I knew supernatural was a thing and enjoyed them thoroughly):
Deanzilla vs. Hydros
Measure of a Man