Sorry this is gonna be a long post (i have some free time right now), but its got pictures
If you are looking to a more complex model, heres a pikachu by Kozasa, Keiichi, which was diagrammed in tanteiden convention book 5. It has nice color changes for the tips of the ears, the stripes on its back, and at the base of the tail
Heres my fold of it: (Its lying down on its belly)
Heres another fold of it, by someone else with better shaping than mine
Theres also some other pokemon i've found:
Tyranitar by Nathan Park (picture and CP from his flickr:
http://www.flickr.com/photos/14661555@N04/)
Gliscor by Nathan Park (picture and CP from his flickr:
http://www.flickr.com/photos/14661555@N04/)
Mew by Nathan Park (picture and diagrams soon? from his flickr:http://www.flickr.com/photos/14661555@N04/)
*check this link out:
http://www.comic-folder.sakura.ne.jp/top.index.html
In that link I also found: (im doing the names by memory because the page is in japanese so i cant read the names)
**all credit for these photos goes to Miyamoto, Shintaro, from his site
***The CP for all of these models is on his page
Bulbasaur
ivysaur
venusaur
charmander
charmeleon
charizard
chikorita
maganium? (the final evolution of chikorita i forget the name?)
cyndaquil
pikachu
delibird
gastly
torchic
combusken
blaziken
treeko
grovyle
skeptile
mudkip
marshtomp
swampert
scizor
kyogre
mewtwo
latios
suicune
celebi
skarmory
articuno
moltres
There was also someone who made all the eevee evolutions (jolteon, vaporeon, flareon, umbreon, espeon, glaceon, leafeon) but i cant remember the designer or where i saw them.... if i find them ill post them here.
EDIT: Found videos tutorials to fold Dialga and Palkia

The same guy also has a squirtle video but i didnt find that model too great so i didnt post it here lol... just click the video and you should see the squirtle in the related videos if you are interested.
Dialga
<embed src="http://www.youtube.com/v/1u6Ium-oLRQ&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed>
Palkia
<embed src="http://www.youtube.com/v/_SzzFvVcurA&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed>
Yes i did play ALOT of pokemon when i was younger
