Traditionally, Japanese-language Pokmon cards have a back design that is different from English-language cards
Wrapping It Up The more I study older sealed product, the more complex I believe the market is
They have also just recently announced Chapter 2 will be releasing in November
Cards like Battle Fader and Swift Scarecrow were an integral part of the game in the early 2010s, but there was one card that had a massive impact on one specific format because of its interactions with other Light-attribute monsters
Card Size is Different Paper Quality difference and Paper Thickness, but this depends on the set too I think, because they may change the paper stock that they use depending on cost of materials you can also ask a Pokemon Professor, they may have insight into fake cards entering the market and be able to give you pointers in spotting fakes
Conversions can shift saturation and brightness, especially in neon-ish blues and deep purples