Yeah, I regret selling New Super Mario Bros. and Mario Kart DS myself :(
I'm really glad I never sold my pokemon games though, although there are a lot of other ones I regret selling. :/
I've never really had a team that had a good strategy to it, it's mainly just made of ones that I saw had good stats. :P
But I am going to add a Dusknoir to try and deal with Scizor's, as I have nothing good to take those down. The other day I was going to start breeding for a Careful natured one, but after looking through almost 2 boxes full of dittos, none of them were Careful nature. >_<
And then when I went to catch some hoping for the right Nature, I remembered that I had sold most of my good pokeballs to buy stat-boosting items. >_<
Oh well, I will get it eventually. :P