Settlers III

Faster building
Press [F12] to pause the game, then immediately press [F12] again to resume.
Then, one minute in game time will have elapsed for all players.

80,000 credits
While playing a game, hold [F8] for approximately twenty seconds, then press G while continuing to hold [F8].

Change view
Press [F1] for a zoomed in, [F2] for a standard, or [F3] for a zoomed out view.

Faster battles
Continuously right click while fighting to keep your warriors in swordplay and your archers firing.