Suppose your opponent (or one of your opponents if it's a 3+ game) already has just over half of each of the Victory cards available in his deck. (For example, he has 4 Provinces, 4 Duchies, 4 Great Halls, and 5+3 Estates in a non-Propserity 2-player game.) You know that your opponent won't make any obvious play mistakes to give you the game, such as trashing his own VP cards for less value.
If you want to continue playing as long as it's still possible to win, as long as any chance of victory exists with perfect shuffle luck and perfect play on your part, what cards and strategies do you look for?
Come up with as many solutions as possible.
Here's everything I can think of:
* VP chips: Monument, Bishop, Goons.
* Curse-givers: As long as you can get the remaining almost-half of all VP cards and deal out more than half the curses, you can win. I won't bother listing every cursing attack possible.
* Variable-value Kingdom VP cards: Gardens, Fairgrounds, Vineyards. If you can make yours worth more than his, then you can win with less than half of the VP cards. Unfortunately, Silk Roads and Dukes don't work, since you can't get more supporting VP cards than he does.
* Masquerade: There's some chance he'll draw an all-green hand and have no choice but to pass one to you. Bonus: make it more likely with Minion. Or go for a KC/Masquerade pin.
* Possession + Ambassador: Make him return green cards to you.
* Saboteur: Destroy his VP cards and replace them with lower-denomination cards. Bonus: make it more likely to hit high-value cards using Highways/Bridges
* Swindler: Convert his VP cards into non-VP cards. (Duchies to $5 actions, Provinces to Peddlers) Bonus: use Highways/Bridges and Swindle things into Coppers or Curses.