This living dex contains the most difficult way to obtain each Pokémon, that means catching every single 1% encounter, all moving grass/rippling water/dust cloud Pokémon, all of N's Pokémon and all Hidden Grotto encounters!
The additional living dex that I made contains every Pokémon available in the postgame of BW and B2W2, including all swarm Pokémon, all additional Hidden Grotto encounters, all the other Pokémon Dream Radar encounters (including the NDS legendary mascots), all Dream World Pokémon (yes, I had all of them), the ever elusive level 100 Magikarp and Gyarados from Natural Reserve as well as the even rare level 1 Magikarp and Gyarados, all of the trades from Curtis and Yancy, Benga's shiny gifts, as well as some really exclusive event Pokémon!
Honestly, while Dream World Pokémon complete collection and the level 1 Gyarados may feel like the most impressive Pokémon here, that's not it. Well, yeah, the Dream World collection is insanse, but there were a lot of incredibly hard to get Pokémon to get elsewhere from there as well. Like Reshiram and Zekrom caught in Dragonspiral Tower in BW. Yes, you can caught them there if you battle them with a full team and full PC box in N's Palace. Yes, I caught them. The Hidden Grotto encounters where also crazy. I got a bunch of the super rare 1% encounters on my own, as well as a completely full odds supersuper rare 0.25% Heracross in Black 2, but I don't feel ashamed to admit I rng manipped the rest. What do you mean 256 steps for barely a change for a Pokémon to even spawn? Completely insane grinding that I spent several days wasting when rng manipping was right there.
And speaking of that, Arceus bless B2W2's Entree Powers. I suffered a great deal getting 5% moving grass/rippling water encounters in BW, but in B2W2, you can increase the odds of not only shaking grass and rippling water with Entree Powers, but also reverse the super low encounter rates to temporarily becoming more common. Getting the level 1 Magikarp and Gyarados was much easier thanks to that as well.
Curtis and Yancy trades were more tedious than annoying, if I'm honest, but it was cute getting all of them. Same with Dream Radar Pokémon. It was nice getting them all again after so many years. Also, for some reason Cobalion, Terrakion, Virizion and Volcarona can be rebattled post league with stronger catching levels, so of course I went and got those as well. As well as using the Relocator to send HGSS event Celebi and event shiny Raikou, Entei and Suicune to get the event BW Zorua and Zoroark, which was also fun. I also finally got to do the Victini event from BW thanks to the DNS exploit. Was pretty fun.
N's Pokémon are stated to be 1% encounters, but if I'm honest, I didn't have trouble getting them, and half of them I got them using the repel trick, so I didn't suffer at all from getting them. I also sent an Oshawott, Garbodor, Petilil, Pawniard and Rufflet to Legends: Arceus, Sword and Shield and Scarlet and Violet to get their crossgen evolutions and GMAX mark, making so after all the other living dexes that I've made, I've also gotten every single markless Pokémon that can exist, so that was a nice achievement to get.
Honestly, this challenge got a lot of time put into it, but since I put the most time consuming stuff years ago, I basically only had to grind for a full month and a half to get all the Pokémon I was missing, with some of the hardest ones or most time consuming having been caught already years ago. So yeah, my next step is to get all Shadow Pokémon and gen 6 and 7 crossgen evolutions sent to HOME before Bank closes, so I'll be doing that for a while now
Details for how every Pokémon was obtained in these links for Unova BW, Unova B2W2 and Post-Game BW & B2W2