If by in-game you mean sets for the game's main storyline, no. The 'What is a good in-game team for...' threads should cover that area sufficiently.
However, if you're making a set for a competitive format in-game, such as Battle Spot, it's allowed. You may also post sets intended for features akin to the Battle Tree.
In the end, the defining factor is whether the set is competitively focused. That's the best measure for it.
