Diamond and Pearl
02 August 2018 - 03:46 PM
02 August 2018 - 04:44 PM
HeartGold and SoulSilver has always been the oldest playable set on PTCGO, mainly because PTCGO originally came out when the Standard format (then called Modified) was HGSS-onwards.
There were hints of older sets on the program (I've seen cards from Majestic Dawn, Legends Awakened, and Stormfront), but they were never fully programmed into the game, so they're completely inaccessible.