Since we're sort of playing the "When did ___ last appear" game...
-Never: Zygarde, Hoopa (and Volcanion but... obviously)
-2003: Kadabra (Skyridge)
-2007: Mantyke, Bonsly, Wynaut, Azurill (DP); Abra (Mysterious Treasures)
-2008: Glameow (Majestic Dawn); Anorith/Armaldo, Castform, Regice (Legends Awakened); Budew (Stormfront)
-2009: Cranidos, Shieldon, Purugly, Happiny (Platinum); Alakazam, Rampardos, Bastiodon, Shellos/Gastrodon (Rising Rivals); Seel/Dewgong, Goldeen/Seaking, Chingling/Chimecho (Supreme Victors); Omanyte/Omastar, Kabuto/Kabutops, Burmy/Wormadam/Mothim, Arceus (Arceus)
-2010: Paras/Parasect, Spinarak/Ariados, Pichu, Igglybuff, Spinarak/Ariados, Mantine, Smoochum (HGSS); Sudowoodo, Stantler, Larvitar/Pupitar/Tyranitar (Unleashed); Gastly/Haunter, Unown, Elekid (Triumphant)
-2011: Chikorita/Bayleef/Meganium, Cyndaquil/Quilava/Typhlosion, Cleffa, Smeargle, Tyrogue, Magby, Mime Jr. (Call of Legends); Ferrothorn/Sawsbuck (Emerging Powers)