I will only go with that wild Pokémon he helped on his journeys and didn't kept for stupid technical reasons:
KANTO: Clefairy (stupid Seymour), Haunter, Jigglypuff
JOHTO: Teddiursa, Houndour, Murkrow, Miltank
HOENN: Spoink (It appearing twice was a big troll move), Shuppet, Nuzleaf
SINNOH: Hippopotas, Riolu, Drifloon
UNOVA: Darumaka, Venipede, Ducklett (him or Cilan)
KALOS: Vivillon (him or Serena), Espurr, Skiddo, Amaura (him or Serena, and without that stupid weather reason they pulled out of nowhere)