Stop dealing with the 98% of the population. If they're so rich, they are now peers of the 2% of the population who rule in various ways. Peasants may have nothing to offer in reward, but queens, nobles, generals, and the heads of merchant empires will want to either control or ally with such powerful figures – before their rivals do.

As a bonus, your cast of NPCs becomes easier to manage. The number of movers and shakers in any one location is small, and instead of "you see a noble and her entourage as you walk through the city", now it's "Lady Deyer greets you frostily; she must be upset by your growing favour with the King."

As a further advantage, their new allies will expect this "new money" to start acting like it, paying for ladies' maids, manservants, cooks, and guards; food, lodgings, wages, and fine gear and clothes for the servants; reception halls, fine silks, feasts, expensive wines, quality horses; and the list goes on. Being rich is expensive!

Stop dealing with the 98% of the population. If they're so rich, they are now peers of the 2% of the population who rule in various ways. Peasants may have little to offer in reward (perhaps fealty?), but queens, nobles, generals, and the heads of merchant empires will want to either control or ally with such powerful figures – before their rivals do.

As a bonus, your cast of NPCs becomes easier to manage. The number of movers and shakers in any one location is small, and instead of "you see a noble and her entourage as you walk through the city", now it's "Lady Deyer greets you frostily; she must be upset by your growing favour with the King."

As a further advantage, their new allies will expect this "new money" to start acting like it, paying for ladies' maids, manservants, cooks, and guards; food, lodgings, wages, and fine gear and clothes for the servants; reception halls, fine silks, feasts, expensive wines, quality horses; and the list goes on. Being rich is expensive!