The Pokemon series is one of the biggest and most successful in all of gaming; having sold more than 350 million units since its debut back in 1996. It's a series that has never been afraid to try out new ideas and it's perhaps this constant innovation that's led to much of the franchise's success over the years.

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Each new generation of games has brought with it a host of interesting ideas and mechanics; many of which have gone on to become series staples. Now that the last of the officially announced Sword & Shield DLC is out of the way, many fans find themselves wondering which of these features they can expect to see returning when the ninth generation of Pokemon games finally arrives.

8 Gen 1: Trade Evolutions

Trading in the Gen 1 Pokemon games

The ability to trade Pokemon with friends was one of the things that made the first two Pokemon games so popular. Not only did players need to utilize the function in order to complete their Pokedex, but there were certain Pokemon that could only evolve into their final forms after being traded. It also gave Nintendo an excuse to sell multiple versions of the same game, although whether or not that's s a good thing is perhaps a matter for debate.

While trading still plays a fairly significant role in the current Pokemon meta, it would be nice to see more Pokemon that can only evolve through trading added to the roster. There were just four of them in the original games and this number has only risen to 25 in the quarter of a century since. That works out at an average of just three new trade evolutions per generation, which seems a little low.

7 Gen 2: Returning To Old Regions

The Kanto, Johto and Hoenn from the Pokemon games

Upon defeating the Elite Four in Pokemon Gold & Silver, players are able to return to the Kanto region in order to catch new Pokemon and battle more powerful trainers. As well as bumping up the total playtime and providing a new challenge, being able to return to the series' first region also serves as a nice trip down memory lane for those who have played the original games.

It's something that has yet to resurface in subsequent Pokemon titles, although could presumably be implemented fairly easily were the developers so inclined. Past regions could even be added through DLC which would at the very least help to gauge fan interest in the idea. Substantial new content in this form would also be a great way to tide fans over between generations and would likely generate some serious profit at the same time.

6 Gen 3: Multi Battles

A double battle in the Gen 3 Pokemon games

For as enjoyable as a one on one Pokemon battle can be, the introduction of multi battles in Gen 3 brought with it a whole new challenge. Now, rather than focusing on just a single enemy Pokemon, players needed to think carefully about their own selections and how well their party Pokemon work as a team.

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The series has played around with double and triple battles quite a lot in the games since Ruby & Sapphire; with the former most recently appearing in Pokemon Sword & Shield. While not all players appreciate the battle type, having the option for those who do seems like something of a prerequisite for developers at this point. At the very least, players should be able to partake in multi battles online, if not with regular trainers in the game.

5 Gen 4: Voice Chat

Approaching Gyratina in the Gen 4 Pokemon games

The fourth generation of Pokemon games introduced quite a few new features to the series, although perhaps the most notable of these was voice chat. This provided players with the ability to communicate with each other during battles and trades; allowing them to relay stats about their Pokemon or simply engage in a friendly spot of banter.

These days, most people use services like Discord to communicate during online play, but it is something that can be done directly through the Switch. Despite this, there are only a handful of games that support the feature, which suggests that Nintendo may have concerns about how it might be used. Due to the young age of many Pokemon players, the developers may well opt to steer clear of voice chat rather than risk facing the wrath of angry parents.

4 Gen 5: Absofusion

Shiny Black Kyurem from the Gen 5 Pokemon games

Black & White may have been two of the more forgettable Pokemon titles, although they did introduce one or two really cool ideas. The most interesting of these was Pokemon fusion, which allowed players to combine their Kyurem with one of two other legendary Pokemon in order to obtain a new, more powerful form.

This idea has been revisited a few times since Gen 5; most recently resurfacing in the Crown Tundra expansion for Sword & Shield. Here, players are once again able to temporarily combine certain legendary Pokemon, although it's a bit more advanced than the original Absofusion. Depending on which Pokemon players choose to fuse with their Calyrex, the resulting form can either be Ice or Psychic-type; thus providing an additional strategic element to the fusion mechanic.

3 Gen 6: Mega Evolution

Mega Charizard X from the Gen 6 Pokemon games

While it would have been very easy for the team at Game Freak to continue to add new branches to old evolutionary lines, they instead opted for a more temporary approach. Mega Evolution allows Pokemon to transform into a significantly more powerful version of themselves for a limited period of time.

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So far, 46 Pokemon have been given Mega Evolutions, with Charizard and Mewtwo each having two. Although many of the more popular Pokemon have already been upgraded in this way, there are still plenty of incredibly powerful monsters that can't Mega Evolve. With this in mind, it seems all but certain that more Mega Evolutions will continue to be added over the next few generations.

2 Gen 7: Regional Forms Of Pokemon

kanto vulpix alolan vulpix

While the designs of some of the Alolan Pokemon left a lot to be desired, the concept of regional forms remains a good one. It was really starting to feel as though the developers were running out of inspiration for new Pokemon and so tweaking some of the older, more neglected ones was in many ways a stroke of genius on their part.

Regional forms were once again included in Sword & Shield and the Galarian designs are, thankfully, quite a bit better this time around. With the new forms often switching types, it provides a brand new way to use some of these Pokemon while also making some of the older ones relevant again. Whatever region the next generation of Pokemon is set in, it seems a safe bet that there'll be some more regional Pokemon residing there.

1 Gen 8: DLC

pokwmon sword shield expansions

When used correctly, DLC can be a great way to extend the life of a video game and has the added bonus of also bringing in some additional revenue for developers. Unlike some of the other big publishers, Nintendo has traditionally been fairly good with its implementation of downloadable content and is pretty fair with its pricing too.

While not quite perfect, the expansions for Sword & Shield offer more than enough to justify their price-tags and have added plenty of new Pokemon and features to the games. There's still no word on whether more of them will be released for the current generation of Pokemon games, but it would be a big surprise if DLC doesn't return to the series in the coming years.

NEXT: Pokémon: 10 Ways You Forgot Gen 8 Changed The Series Forever