Just realised an awesome combo: Chancellor + Inn. Like, if you ever wanted a reason to buy a Chancellor, Stash is nice, Counting House can be cute, but Inn could be game-changingly powerful.
So you want to start doing this in the mid to late game, once you've got some nice action cards happening. Then, every time you get Chancellor + $3, flip your deck, buy an Inn, and set yourself up with your selection of action cards. Put two King's Courts on top with your best actions. Or put up a stack of Villages and Goons. Though you may need to be careful about the number of terminals you stack up, as you don't get to choose the order. If you're clever, you might throw up another Chancellor as well, although this will only work if you only use half your action cards at a time, or you have a Courtyard or Mandarin to make sure you can save your Chancellor for when all your action cards are gone from your play area.
Of course, most of the power here is in Inn's gaining effect. But this is by far best done when you're as close as possible to reshuffling, and Chancellor not only gives you more "chances" (I made a pun!) to get there, but it makes sure there aren't a stray card or two left on your deck when you buy the Inn.
Another nice thing about this is once you have some Inns in your deck, you can use it to discard anything you don't want this turn but want for your next megaturn.