I gave you the source of 4 actions that is least dependent on other circumstances. It is the best answer I can give. There are not even any cards that give you 2 actions without any dependency on the circumstances. Just the other day I played all the other cards in my hand, then played a Festival. It didn't give me +2 actions. Joey just said, "Damnit Alex, stop putting Dominion cards in your Magic decks, it's not funny anymore."