My top list of the Pokémon mangas I've read are:
1.
Pokémon Adventures (Ongoing,
50 45 volumes in English - the
Pokémon Black and White are shortened, only 3-4 chapters per volume), 41 in Japanese. RS, FR & LG and Emerald arcs are Singapore exclusive)
2.
Phantom Thief Pokémon 7 (1 volume, Singapore exclusive)
3.
Pokémon Diamond and Pearl Adventure! (8 volumes, completely different series than
Pokémon Adventures)
4.
Pokémon Gold & Silver: The Golden Boys (3 volumes, Singapore exclusive)
5.
Pokémon Battle Frontier (1 volume, Singapore exclusive)
6.
Pokémon Mystery Dungeon: Ginji's Rescue Team (1 volume)
I have ordered the all four volumes of
The Electric Tale of Pikachu and gotten three of them so far, so I haven't read it but it looks good.
If you want to try The Electric Tale of Pikachu make sure you get the volume editions and not the magazine editions. The magazine editions miss the last chapter and I also think that some chapters aren't in correct order. You also have to get four magazines in order to get the contents of one volume, that makes it 16 magazines. I got the Viz editions that are censored, since they are more tasteful than the Singaporean Chuang Yi editions that only have the first volume censored. If you're wondering what's censored, let's just say that the artist likes to draw the females "well-equipped". Viz covered it up pretty good though from what I've seen.
The easiest way to tell the difference is that the volumes have "Viz Graphic Novel" written on it while the magazines have "Viz Comics" written on it. Bulbapedia also have
a great article about it which makes it easier to compare the editions using cover pictures.
There's also a Singapore exclusive manga called
Pokémon Pocket Monsters. It's popular in Japan and it's humor oriented. Looks ok, but I haven't read it.
Movie adaptions are also available, but I don't think it's worth getting a manga based on a movie. The same goes for the Singapore exclusive direct anime adation called
Ash and Pikachu and the manga adaption of the first two Pikachu shorts named
All That Pikachu! Animanga.
There's a Viz exclusive graphic novel called
Pikachu Meets the Press, but it's a comic and not a manga, it's poorly drawn, "Americanized" and not very good, I've read it.
There's an animation comic called
Pokemon TV Animation Comic: I Choose You!, but it doesn't look too impressive.
There's a shojo Pokémon manga (= manga aimed for girls) named
Magical Pokémon Journey, which is known in Japan and it's fanbase as PiPiPi. The First seven volumes were released by Viz and Chuang Yi and the last three were only released by Chuang Yi in Singapore.
That is all Pokémon manga that has been released in English.
The Viz mangas can be bought at bookstores and websites in North America, Europe and South Africa.
Here's some websites that sell it:
store.viz.com,
Amazon.com,
Barnesandnoble.com,
Booksamillion.com,
Walmart.com,
Target.com,
Buy.com &
Overstock.com
Just make sure you buy the 2nd edition of Pokémon Adventures and not the 1st edition, if you're planning on buying it. The 1st editions are split up in many issues, while the 2nd editions are collected in 200 page volumes, like the Japanese original volumes. The 1st editions are flipped to a left to right reading format, while the 2nd editions are preserved in the original right to left format. (Don't worry you get used to reading the panels from right to left after your first volume). The 1st edition is however out of print, so they're only sold used.
Here's pictures of the Viz 2nd edition covers of vol. 1-14:
http://bulbapedia.bulbagarden.net/wiki/List_of_Pok%C3%A9mon_Adventures_volumes
Here's a complete list of all Viz 2nd edition
Pokémon Adventures +
Pokémon Diamond and Pearl/Platinum +
Pokémon Black and White:
http://www.amazon.com/Pok%C3%A9mon-Adventures-Pok%C3%A9mon-Special/lm/R9QHMJMB47HMZ/
I recommend that you get the box sets. They are cheaper and come with a nice poster and box. Especially for Pokémon Black and White, since they only have 3-4 chapters per volume.
If you buy the Red & Blue and Gold & Silver Box Sets you'll save $26 compared to buying the individual volumes. If you buy the Black and White Box Set you'll save $17 compared to buying the individual volumes.
If you buy the Pokémon Diamond and Pearl Adventure! Box Set (not same series as Pokémon Adventures, completely different) you'll save $18 compared to buying the individual volumes.
Pokémon Adventures
Pokémon Adventures Red & Blue Box Set (Vol. 1-7):
Pokemon Adventures Gold & Silver Box Set (Vol. 8-14)
Pokémon Black and White Box Set (Vol. 1-8)
Other Pokémon mangas
Pokémon Diamond and Pearl Adventure! Box Set (Vol. 1-8, complete, not same series as Pokémon Adventures, completely different):
If you want a non-Viz Pokémon manga or an out of print Pokémon manga, just tell me which one and I'll try find it for you.
Btw, there's about 60 different Pokémon mangas in total, but most of them are untranslated
The two biggest series are
Pokémon Adventures and
Pokémon Pocket Monsters:
Pokémon Adventures currently has 50 volumes, of which 45 are translated into English.
Pokémon Pocket Monsters and it's sequels have currently 29 volumes combined of which 20 have been translated into English in Singapore.
Here's some great articles about Pokémon manga. I've learned very much from them.
http://bulbapedia.bulbagarden.net/wiki/Pokémon_manga
http://dogasu.bulbagarden.net/manga.html
http://en.wikipedia.org/wiki/Pokémon_(manga)