And we'd expect Ravenclaw members to already be using any clever potions or at least have rules against them (either imposed by the school or by themselves as 'cheating'). In canon, they all know about the Ravenclaw diadem which is supposed to make you more clever. So it's reasonable if there were any such thing, Harry would have been told about it (everyone knowing his interest in self-improvement or being more clever), heard of it, or read about it by now.