>>31952826If you use Soundhaxx to easily hack your 3DS, you can get Red, Green, Blue, Yellow, Gold, Silver, Crystal, Ruby, Sapphire, Emerald, FireRed, LeafGreen, X, Y, OmegaRuby, AlphaSapphire, Sun and Moon for free, all on the same console.
Doing this, you can transfer your Pokémon from game to game all the way up to Sun and Moon by using the program PKHex.
However, as for the time being, you can't get Diamond, Pearl, Platinum, HeartGold, SoulSilver, Black, White, Black 2 and White 2 on the 3DS via hacking, so you'd either have to buy them as physical cartridges or emulate them on your computer (also really easily done, and you can still transfer your Pokémon via PKHex to your 3DS games).
Plus, if you want the FULL Pokémon experience, I suggest playing Pokémon Colosseum and Pokémon XD: Gale of Darkness too. These are GameCube games, so you'd either have to get physical copies or emulate them on you computer. Again, if you choose to emulate, you can still transfer your Pokémon from these to your 3DS games.
Furthermore, Pokémon Ranger, Pokémon Ranger: Shadows of Almia and Pokémon Ranger: Guardian Signs are also very great games, and they allow you to obtain Mythical Pokémon such as Manaphy, Darkrai, Shaymin, Deoxys and Heatran, as well a special Riolu.
Pokémon Dream Radar is a free app you can get on your 3DS as well; it's a small game that allows you to catch some extra Legendaries for Black 2 and White 2.
And if you have a Wii, Pokémon Battle Revolution and My Pokémon Ranch also give you special Pokémon, such as Surfing Pikachu and Mew.
Also, you should really try out the Pokémon Mystery Dungeon series. You can't transfer anything to your main games, but they have great gameplay, great stories and they WILL make you cry.