Ninetales appeared in the first generation of Pokémon games, but was only available in Blue and Yellow; Red players had to trade for Vulpix. (Red got Growlithe and Arcanine instead.) This continues through most of the games:
- Generation I: Available in Blue and Yellow, trade to Red (and Japanese Blue)
- Generation II: Available in Silver, trade to Gold and Crystal
- Generation III: Available in Ruby, Sapphire, Emerald, LeafGreen, and XD; trade to FireRed and Colosseum
- Generation IV: Available in Diamond, Pearl, Platinum, and SoulSilver, trade to HeartGold
- Generation V: Available in Black, White, Black 2, and White 2
- Generation VI: Available in X and Y
Generations V and VI are the only instances in which Ninetales can be caught in the wild; otherwise, it must always be evolved from Vulpix.
Ninetales also appears in several of the side games released over the years. (Bulbapedia tells me it was even an important NPC in the first Mystery Dungeon. Maybe I'll have to dig out my copy and try it again sometime.) Ninetales appeared in the following games:
- Trading Card Game ∗
- Stadium 2
- Pinball: Ruby & Sapphire
- Mystery Dungeon Red/Blue Rescue Team
- Mystery Dungeon Explorers of Time/Darkness
- Ranger: Shadows of Almia
- Ranger: Guardian Signs
- Rumble Blast
- PokéPark Wii: Pikachu's Adventure
∗ In Pokémon Trading Card Game (released for the Gameboy Color in 2000), Ninetales is written as "Ninetails." This misspelling is frequent enough on the internet, but that's the one time I saw it make it into a game. Sigh.
Given the high number of Pokémon spinoff games, it's entirely possible I missed a few — if you know of any other games Ninetales appears in, please drop me a line!