>Heracross
Great choice, it knew Sleep Talk, Bug moves, and Fighting moves. It was the perfect choice for Darkrai, but it didn't turn out well.
>Torkoal
Borderline retarded. It has never won a match.
>Gible
Stage 1 Dragon is idiotic, even if it does know Draco Meteor and Rock Smash. It's a waste on the Garchomp line anyway. The line about it supposedly beating Darkrai if it hit was pretty stupid.
>Sceptile
Darkrai knew Ice Beam, so although Sceptile was a fucking tank, it was a dangerous choice. Still, it managed to finally beat it, proving its usefulness.
>Swellow
Really no reason to use this. It's one of his average bird Pokémon.
>Pikachu
End-of-the-series Pikachu is always a good bet. It managed to be equal to a Latios, a Legendary it had a type disadvantage to.
Gible, Torkoal, and Swellow were bad choices. Sceptile and Pikachu were iffy choices, but the one that proved best. Heracross was a really smart choice, though it couldn't win. If he just used Sceptile and Pikachu in that order, he'd be 2 for 2, and maybe we'd actually get to see what his other 4 Pokémon were.