If you're up against the last gym badge and for the Elite 4 for the first time. What pokemon that you've caught and trained in random battles are the strongest? Mine are
Magmar at level 49 Keldeo at 60 now the weird blue jellyfish that looks like a royal king the red octopus since its got ice beam handy to use against dragons and some flying Absol Wailmer - good for being a Surf slave and Dive the bat that has a heart shaped nose. Pretty useful during some battles. That and I used him for Fly Magnezone - great for taking care of any water and flying pokemon
For my first B/W2 run, in which I only used pokemon I had caught in that game rather than trading for my own team?
Caught that Minccino in the Hidden Grotto Bianca takes you to, noticed it had a really good nature, plus that it had its dream world ability Skill Link, and pretty much threw it onto my team right there right then.
Gave it Tail Slap, Rock Blast, Bullet Seed and Wake-Up Slap, and made it hold a Scope Lens for boosted critical hit chance. The damn thing ended up slaughtering just about everything I met. At level 60, it defeated the White Kyurem at the end in one turn with Rock Blast.
I am never going to underestimate adorably cute little fluffy things in these games ever again.