Make a better world. Fight corruption. Better the lives of the commoners somehow. Build lasting humanizing institutions.
Be the best at something trivial. Build the best tavern, for instance. Maybe that means traveling around the globe to find new recipes, ingredients, and things to put on the wall. Maybe you decide you want to make your tavern travel the planes and serve exotic customers.
Wage a crusade against a single foe. I've often thought it'd be amusing to making a goal of exterminating goblins from the world, for instance.
Prevent a war. This could involve lots of intrigue, espionage, assassinations, sagotage, influence, etc.
Colonize the moon. With magic it'd probably be possible.
Create a zoo. Seek out exotic new species to dominate and bring them to your menagerie.
Run a city/barony.