What's the worst card in your opinion?
Then, select other kingdom cards that would make it the best win condition.
Counting House is one of the weakest cards by itself. But paired with cards like Travelling Fair (to topdeck Copper), Watchtower (to draw Coppers immediately), and maybe Stables or Sifters (to find your Counting House), it can actually become a powerful payload card for big money turns. Throw in a source of extra buys like Market, and suddenly those Coppers can turn into a lot of Provinces!