The manga would sometimes reference simplistic games like table hockey or even toys that react to sound, some were more complex including the aforementioned card game against Kaiba or a chess like game using small monsters and while theres clearly some logic as to how the game plays out so readers can follow along, there is no design document explaining all the rules of these games simply because thats not what the manga is trying to do
Searching for a specific card on eBay returns a mess of results: different conditions, lots (multiple cards sold together), misidentified cards, promotional listings, and auction results mixed with Buy It Now sales
Expect 15% appreciation in 2025 with Z-A tie-ins
Most fakes tend to be lighter because they use cheaper, single-layer cardstock
B Seraphimon: To pass this point you must first defeat me
It has really been fun ripping these packs open to find the wonderful cards inside