I can't seen to find a natural expression for "vast collection", as in:
I have a vast collection of baseball cards.
Literally there is 莫大なコレクション, but that seems pretty unnatural and I don't see it used online much. I know there are other adjectives like 巨大 or 大規模, but I can't find a good combination. Also, I am not sure if 集まり would be better than コレクション or if there is another common word pairing here.