Kanto
The Kanto games have always featured all the Kanto Pokémon and nothing more. Though from what I have understood, LGP/E added Meltan and Melmetal to the Kanto Pokédex? So that’s at least something. The Kanto games does a good job at focusing on their own Pokémon, but I feel that focusing only on the Kanto Pokémon alone does not work anymore because the Kanto part of the Pokédex have gotten fractured over the years. Having the Kanto Pokémon alone without their evolutionary relatives from the other regions (notably Johto and Sinnoh) makes several Kanto lines feel incomplete. I think it was acceptable in FR/LG, but it just feels wrong that they decided to stick with it in LGP/E too. When they make more Kanto games in the future, I really hope those will have some sort of Pokédex expansion.
Johto
Both versions of the Johto dex mainly features all the Kanto and Johto Pokémon. HG/SS added a few of the new evolutions to old Pokémon, but only 5 out of a total of 23 (as has been stated earlier). While the Johto games feature all the Johto Pokémon in their regional dex, the issue is that the Johto Pokémon don’t get enough attention in their own games. Most of the Johto Pokémon are rare/uncommon or even unavailable until the post-game in their own region! As for the dex on the whole, I think that the Johto dex is more in need of a revamp as opposed to an expansion. Like with Kanto, the Johto part of the dex is fractured. It relies too much on other regions to feel complete, and because HG/SS failed to include all the Pokémon from other regions that are related to the Johto Pokémon, the only time the Johto dex felt complete was in G/S/C. The Johto dex does not need all the Kanto Pokémon, just keep those that are relevant for their relation to the Johto Pokemon (or the story) and remove the rest, then add a bunch of Pokémon from the other regions instead (notably all evolutionary relatives to the Johto Pokémon, apart from Kanto, I think most of them are from Sinnoh). I think there is a lot of potential to make something great out of both the Johto games, the Johto Pokémon and the Johto regional dex, but the question is if they want to do it.
Hoenn
I think the Hoenn games do an excellent job at showcasing their own Pokémon. And OR/AS added all the evolutionary relatives that were new since R/S/E, which is excellent. Unfortunately, there were only 9 in total, so the dex size didn’t increase as much. On a positive note, Hoenn isn’t anywhere near as fractured as Kanto, Johto and Sinnoh, so it can stand on its own a bit better. Regarding the other Pokémon that are in the dex, Kanto has considerably more than Johto which I guess isn’t too surprising. Thinking back on the Pokémon that appear in the Hoenn games apart from the Hoenn Pokémon, I remember seeing more from Kanto than from Johto in general. Some that stand out are the Geodude, Tentacool and Oddish lines. Though there are a few I can remember being relatively common from Johto too, like the Slugma and Chinchou lines.
Sinnoh
The Sinnoh games were the first in the series which featured two different regional dexes for the same region in the same generation.
First of all, there’s the D/P dex. It has problems in many areas. Looking at the available Pokémon, the most glaring flaw is that it does not even feature all the new Pokémon! D/P are the first and so far also (fortunately) the only games where not all of the new Pokémon are in the regional dex. The D/P dex has 81 from Sinnoh out of a total of 113, which is 72%. From the older regions, Kanto gets the largest amount just like in the Hoenn dex, while Johto is second and Hoenn last. Kanto has twice as many Pokémon as Hoenn, with Johto being in-between, having 10 less than Kanto and 6 more than Hoenn.
Platinum introduced a much-needed dex expansion to the D/P, which was also a first for the series. One very interesting thing to note is that a few of the legendaries and mythicals are still left out. This makes the Sinnoh games the only ones to never have featured all of their own Pokémon in any of their regional dexes. These 7 Pokémon were left out from the Platinum dex: Cresselia, Regigigas, Heatran, Phione, Darkrai, Shaymin and Arceus. It also means that those 7 are the only Pokémon in the entire series to never have been a part of any regional dex. Apart from that, 19 Sinnoh Pokémon were added to the Platinum dex, bringing the number up to 100, which is almost half of the total dex number, so that’s great. Kanto and Johto got 14 more Pokémon each, while Hoenn only got 12. Still somewhat uneven, the difference between Kanto and Hoenn increased from 16 to 18. Though it is still not that bad, other regions have it much worse as we shall see further below. The important thing is that Platinum gave more focus to the Sinnoh Pokémon, which is great.
Unova
The second region to have two different dexes in the same region. They are also quite a bit more different from each other compared to all other regional dexes that has appeared before or after them (so far).
B/W has only the 156 Unova Pokémon and nothing more. Personally, I like this a lot. I think B/W does an excellent job at showcasing their new Pokemon since they only showcase them and nothing else during the main game. Not sure what else to say. I guess the negative could be that the dex might feel small compared to most other modern dexes, but I had no issue with it at its time and I don’t think I would have any problem with it if I were to replay B/W nowadays either.
B2/W2 made another dex expansion and almost doubled the size of the Unova dex, adding more Pokémon from all previous generations. As I have talked about earlier, I think they did a very good job since all the older regions a fairly even distribution between them, the difference being only 11 between the highest (Hoenn) and the smallest (Johto & Sinnoh). I think the B2/W2 dex had the best balance between the new and all old generations out of all the large regional dexes in the series so far.
In general, I think the Unova games really did an excellent job at… pretty much everything, but the regional dexes was definitely one thing. Having two vastly different regional dexes like this allowed the games to complement each other very well instead of one game pair being obsolete because of the other, like what happened for the Sinnoh and Alola games.
Kalos
X/Y has the largest regional dex to date, with 457 Pokémon in total. Kanto has the most here with 111 which is 24% of the total dex size, almost a fourth. After that is Unova which is very closely followed by Hoenn, then Kalos itself, Johto and somehow Sinnoh last. Looking at the dex numbers, there are three old regions which have more Pokémon than Kalos itself. While Kanto has a large number here, it never bothered me that much and I didn’t notice it when playing through X/Y. I think the large total number combined with the great Pokémon distribution and variation on the routes in Kalos made the Pokédex feel very diverse, Kanto or any other region never felt like it took over too much, unlike how it felt in a certain other region.
We never got a follow-up game to X/Y, but I really wonder how “Z” would have handled the regional dex. A Pokédex expansion feels a bit unnecessary when you already have the largest regional dex in the series, maybe they would have done a revamp or something instead? Or maybe they wouldn’t have done anything at all regarding the dex size, just shuffled around the encounter slots a bit like follow-up games usually do. I guess we will never know.
Alola
I said that there was one region where it became more of a problem that Kanto took over too much of the dex. And it is this one. Here, it became much more of an apparent problem. Like with Sinnoh and Unova, there are two different Alola dexes, so let’s talk about both of them in order.
First of all, we have the S/M dex, it has a total of 87 Kanto Pokémon! The number is lower than in X/Y, but it is higher in terms of percentage: 29%, more than a fourth and close to a third. Kanto definitely got the Pyroar’s share here, which is not cool. Alola itself is second at 81 which is 27%. The other regions got considerably lower, having 33 at the most for Hoenn and 14 at the lowest for Kalos! Which is a bit sad. The statistics for the S/M dex are really sad to see now that I take a closer look at them. I think S/M has the worst regional dex of all games with a large regional dex (300 Pokémon or more). S/M has a ton of issues on the whole, a very apparent one is how they really needed a better regional dex.
Fortunately, US/UM gave the Alola dex a much-needed expansion. They tried to make things more even between the older regions, and I think they mostly succeeded. Kanto now has 98 Pokémon which is 24%, the number is higher than in S/M but the percentage is lower. Thankfully, the other regions got their numbers increased as well. Alola itself got 5 more Pokemon for a total of 86 as opposed to 81 in SM, the others got better too with Johto and Hoenn going up to 51 each. Kalos still has the lowest but 34 that is way better than just 14! Sinnoh got the least new Pokémon, it rose from 29 to 35 with just 6 new Pokémon in total. While I think the Alola dex could have been even better than in US/UM, it did at least improve upon the dex in S/M just like how US/UM improved upon S/M in most other areas, so that is excellent.
Galar
The latest generation, and the last regional dexes that exist as of now. Since S/S have several dexes to talk about, I’ll go over all the relevant ones in order.
First of all, the main Galar dex. It followed in the footsteps of US/UM with a total of 400 Pokémon which is good. Interestingly, Kanto is not at number #1 for once! Instead, Unova takes the spot with 85 Pokémon. That is 21%, slightly more than a fifth of the whole dex. Galar itself is second, and then we get Kanto at third place. The others are relatively even with variations between 42 at the highest (Hoenn) and 32 at the lowest (Kalos, which somehow ends up at the bottom again, sadly). I think it did a way better job than the S/M Alola dex even if things definitely could have been better and more even here as well. Unova got a bit more than it should have had, the same goes for Kanto to an extent.
The Isle of Armor goes back to having a smaller dex for this sub-region. In this dex, Kanto is the biggest since it has 53 Pokémon which is about a fourth, Unova is second and has 43 Pokémon which is about one fifth. The others are much lower, Galar itself is the biggest of them but it only has 22 Pokémon, just barely beating Johto and Sinnoh. Kalos got the lowest number once more, with a total of 14 Pokémon. But apart from Kanto and Unova, the older regions are all quite close to each other.
For the Pokémon that got added with the IoA, Kanto is at number 1 and Unova second. Hoenn got the last spot with only three new Pokémon! The others didn’t exactly get a lot either, Johto got the most at 13 new Pokémon. It is a bit strange that Hoenn got so few seeing as it has the third largest number of Pokémon in total, which was represented in the main dex here Hoenn was the third highest.
Next, the Crown Tundra dex. This one is interesting. Unova gets the #1 spot here, closely followed by Galar itself (which of course is a very good thing), and then Hoenn, with Kanto only at 4th place! Very interesting. Johto, Sinnoh and Kalos got less, with Alola being the big loser here at only 4 new Pokémon. Which is very odd and unfortunate.
As for the Pokémon that got added with the CT, Hoenn got the most here, which could be seen as a nice compensation for how little it got with the IoA. Kanto is number 2 (why am I not surprised?) while Unova got very little compared to in both the main game and the IoA. It is at number 3 but it only has 8 new Pokémon, it is barely larger than any of the other small ones (which barely got anything either). And Alola is the big loser with a total of 0 new Pokémon. Though many did get added to the games with the update even if they aren’t a part of the CT Dex.
There’s also the full dex: Galar + Armor + Tundra (not going to comment on Galar + Armor since I think that is irrelevant at this point). Here, we see that Kanto and Unova are tied at first place! Galar is at third place, which is good. Hoenn is at fourth place. The others got a lot less, Alola is the loser once more with Kalos not far behind. Interesting. Johto and Sinnoh also have considerably fewer Pokémon compared to the others.
There’s one more thing. I wanted to take a look at all the Pokémon that are available in S/S on the whole at the moment (including Pokémon that are in the games but not in any of the dexes). Shoutout to
DreamPrince for posting the statistics earlier, and to
Merritt for writing them down in the first place. However, I noticed that the actual number for the Alola Pokémon that are in the games was wrong. It is 75, not 70.
I decided to not do a graph or anything, just a (hopefully) easy-to-read list for each region which shows how many Pokémon are in the games and how many are missing, and how much both of those are in terms of percentage seen to the total number of Pokémon from each region.
Kanto
117 Pokémon in the games (77,5%)
34 Pokémon missing (22,5%)
Johto
56 Pokémon in the games (56%)
44 Pokémon missing (44%)
Hoenn
87 Pokémon in the games (64,5%)
48 Pokémon missing (35,5%)
Sinnoh
68 Pokémon in the games (63,6%)
39 Pokémon missing (36,4%)
Unova
126 Pokémon in the games (81,8%)
30 Pokémon missing (19,2%)
Kalos
52 Pokémon in the games (72,2%)
20 Pokémon missing (27,8%)
Alola
75 Pokémon in the games (87,2%)
11 Pokémon missing (12,8%)
Meltan and Melmetal
2 Pokémon in the games (100%)
0 Pokémon missing (0%)
(wasn’t sure where to include them so I gave them a section of their own)
Galar
89 Pokémon in the games (100%)
0 Pokémon missing (0%)
(Galar is obvious, but I decided to include it anyway)
Looking at these stats, we can see the following (discounting Galar):
Alola has the most Pokémon included in terms of percentage, while Unova has the highest number of total Pokémon in the games. Once more, Kanto is not at the #1 spot for either category even if it is at #2 for the total number of Pokémon in the games. But since it has the second most Pokémon, maybe that’s actually fair? Looking at the others, Unova has the most Pokémon and is at #1 as said, Hoenn has the third most and it is at #3, Sinnoh the fourth most and it is at #4, but then the trend breaks as Johto has the fifth most but is only the one with the 6th most Pokémon in the games, being beaten by Alola while it isn't much higher than Kalos either.
As for the missing Pokémon, Johto has the highest number of missing Pokémon in terms of percentage, while Hoenn has the highest number of missing Pokémon in terms of the actual number. Sinnoh is second in both categories though. Interestingly, those three all have pretty large numbers of Pokémon on the whole, their total Pokémon number is smaller than Kanto and Unova but bigger than Kalos, Alola and Galar. It is a bit strange how two of the regions with a smaller number of new Pokémon got more than three of the regions with a larger number of new Pokémon in terms of percentages.