1999~2001 - Pokmon Gold/Silver/Crystal
After Pokmon took over the world in the form of side games, anime, and dozens of toys, it was finally time for the series to have its first true sequel. Taking place three years after the first game and set in a whole new region, Gold and Silver had a similar story of becoming a Pokmon Master, but it introduced so much to the series. 100 new pocket monsters joined the stable, a day night cycle was added, you could now breed Pokmon, and thanks to the Game Boy Colors main characteristic, the adventure was in color too.
GS also gave the series some needed continuity, especially in the endgame that reintroduced the Kanto region and all its Gym Leaders, including Red, the protagonist of the last game. The third game in the set, Crystal, upped the importance of story even more, giving a ton of background to the Legendaries that youre chasing throughout the game. And in a tradition that continues to this day, it let players choose the gender of the hero. Gold, Silver, and Crystal ushered in a new era for Pokmon, proving the series was here to stay.
2000 - Pokmon Puzzle League/Pokmon Puzzle Challenge
Intelligent Systems excellent tile-matching puzzle game Panel de Pon is noteworthy in that its never seen a release in North America in its original form. It was rebranded with Yoshis Island-themed visuals in the late SNES release Tetris Attack, and then redone again years later as Pokmon Puzzle League and Pokmon Puzzle Challenge on the N64 and Game Boy Color. Pokmon Puzzle League is also historically interesting in that it never received a Japanese release, as it was built and tailored specifically around the 4kids-produced dub of the anime series. The N64 version is available on the Wiis Virtual Console.
2001~2002 - Pokmon Mini
Building upon the ideas of the Pocket Pikachu, Nintendo introduced its smallest cartridge-based system to date in 2001. The Pokmon Mini had a similar form factor to the Pocket Pikachu, with the added feature of interchangeable, teeny-tiny game cartridges, each containing a different, simplistic game. The unit lacked Pocket Pikachus pedometer (and the Pocket Pikachu 2s color display), but featured an infrared port for transferring data, limited force feedback, a shock detector, and a realtime clock function. The units were released in Pokmon-themed colors: Chikorita green, Wooper blue, and Smoochum purple.
The system proved to be very short-lived outside of Japan, with only four games (Pokmon Party mini, Pokmon Pinball mini, Pokmon Zany Cards, and Pokmon Puzzle Collection) being released in North America. Japan got new releases up through the end of 2002, including Pokmon Race mini, Pichu Bros., and Togepis Big Adventure. The systems lifespan was just under a year in every territory it saw release in, making it one of the least successful Pokmon ventures. We wouldnt see another dedicated Pokmon portable unit until 2010s Pokewalker.
2002~2005 - Pokmon Ruby/Saphire/Emerald
By the time the third generation rolled around, the series got a graphical upgrade on the Game Boy Advance to go along with 135 new monsters added to the series. Another story of a kid going out into the world to become a Pokmon Master, introduced some major new concepts to the series. You had double battles, increased EV and IV training, and each you Pokmon caught became more specialized thanks to individual Natures and Abilities. Some may have complained at the time it was too similar to previous games in the series, but the truest fans could tell this was an adventure all its own.
2003 - Pokmon Channel
Some titles are forgotten for very good reasons, and Pokmon Channel is a prime example of this. Make no mistake about it--Pokmon Channel is a terrible game, offering little in the way of fun or even basic interaction. In many ways, it feels like a prototype for the numerous awful, effortless Wii barely-games that flooded the market.
Pokmon Channel involves you and your Pikachu pal testing out a new television network developed by Professor Oak to entertain both Pokmon and trainer alike. You watch terrible television, broken up by brain dead, barely interactive minigames. You can leave the house to talk to wild Pokmon and earn in-game cards, but by and large the majority of the game is you and Pikachu vegging in front of the tube, no doubt getting fat on Mountain Dew and canned Slowpoke tails. The lack of, well, anything in Pokmon Channel is no doubt why its barely remembered why would anyone think a game based around watching TV was a good idea?
2004 - Pokmon Box
Not so much a game as a utility, Pokmon Box allowed you to transfer and store up to 1,500 generation 3 Pokmon from a GBA cartridge to a GameCube memory card using the GBA link cable. It could also be used to play Ruby/Sapphire on a TV without the need for the Game Boy Player add-on. Its not a particularly exciting piece of software, but we wouldnt be doing our jobs if we scratched over it.
2004 - Pokmon FireRed/LeafGreen
Ruby/Sapphire was exciting in how it embraced the tech of the GBA, but it had one big drawback for longtime fans of the series: It couldnt communicate with the older entries in the series. Pokmon from Red/Blue/Yellow/Gold/Silver/Crystal were stranded on their original carts, unable to transfer off the Game Boy. To remedy this lack of First and Second Gen monsters, Game Freak did their first remakes in series history, transforming Red and Blue into FireRed and LeafGreen. It retold the story of the first games, but still reflected many of the improvements made in the past eight years, especially the ones from the Third Generation.
2005 Pokmon Dash
The first Pokmon game on the Nintendo DS was hardly Diamond/Pearl--it was this oddly experimental little racing game from early 2005. Playing as Pikachu (or other Pokmon in multiplayer modes), the player uses the DS stylus to guide your Pokmon competitor around the track in a madcap race to tag various checkpoints scattered around the tracks. There are different types of terrain to keep aware of, and plenty of scattered power-ups to grant your Pokmon an added boost.
Though it might not have been a rip-roaring success, Pokmon Dash certainly left behind some inspiration for later titles, as the game bears obvious similarities in control and theme to the Pokeathlon minigames in HeartGold and SoulSilver. It was also one of the first games to feature connectivity via the DSs built-in Game Boy Advance cartridge slot, allowing players to play special courses shaped like the Pokmon in their Ruby/Sapphire/Emerald/FireRed/LeafGreen teams. Finally, Pokmon Dash delivered the official introduction of Munchlax, keeping a tradition of introducing upcoming Pokmon through spinoffs and other media going strong.
2005~2010 Pokmon Mystery Dungeon series
Chun Soft is quite a famous developer in Japan, and one of their premiere franchises is the Mysterious Dungeon series of roguelikes. Its unknown how and why they were approached to transplant the world of Pokmon into their dungeon-crawler formula (perhaps Nintendo was impressed by their previous efforts with the Dragon Quest series), but the result has been the Pokmon Mystery Dungeon series. The games take place in a world seemingly disconnected from the usual Pokmon setting, where Pokmon and only Pokmon exist and interact with each other, teaming up and going on rescue missions in randomly generated dungeons. The series has never been particularly well received in North America. Its typically viewed as too obtuse and frustrating for a younger audience, but too dumbed-down for the small but devout roguelike fanbase. Despite this, the games keep on getting released abroad--save for the recent batch of WiiWare Pokmon Mystery Dungeon titles, which look to remain Japan-exclusive.
2006~2010 - Pokmon Ranger series
Not all places in the wide world of Pokmon utilize Poke Balls to train and capture their Pokmon. In the Pokmon Ranger series, you take the role of a sort of nature protector who subdues wild Pokmon with the help of a special device called a Capture Styler, which traces rings around them until theyre friendly enough to work with. This sub-series remains widely available and has been quite well-received, no doubt due to a bonus provided in the initial releases: the Ranger games are the easiest way to obtain the rare Manaphy in Diamond/Pearl/Platinum.