Here's my collection. The two sections represent before cardistry and after. Previously I had multiple decks of cards mainly for memory competitions. I wasn't too concerned about quality, I just wanted decks with four pips because of the way I would handle them during memorisation. They are mainly bridge sized, a mix of plastic and card. There is also one deck there used by Ben Pridmore when he broke the world record for most decks memorised in an hour.
At the bottom are my new decks, acquired since I started cardistry. I see cards in a completely different way now, with the quality of the stock and tuck case becoming much more important to me. I look forward to expanding the lower section soon!