Except for the Founding Fathers, who deliberately created a limited government with a Bill of Rights, and George Washington who, incredibly, turned down an offer of dictatorship.
Tecumseh, Malcolm X, Angela Merkel, Cincinnatus, Eisenhower, and Gandhi all come to mind.
George Washington was surely an exceptional leader but he isn't the only one.
It shows how rare this is.
More often what happens is that leaders make small and often imperceptible choices to not amass more power over time, and that series of choices prevent the scenario like what you're describing from occurring.
Can you name a US President, other than Washington, who reduced the power of the Presidency? All the ones I can think of increased it.
Passing up absolute power isn't the only way that a leader can show humility and grace, true leadership is more subtle and is expressed in the day to day decisions that a leader consciously makes which strengthen institutions rather than consolidate power.
Dwight Eisenhower led the largest army ever fielded during war and afterwards became President yet yielded his power and warned against the undue influence of the industrial-military complex, a system that he could have easily exploited for personal gain.
Gerald Ford pardoned Nixon not for personal gain, but because he believed it was best for the country knowing that it would cost him in the next election.
Outside of the presidency civil rights leaders like Martin Luther King Jr. and Malcolm X held immense informal power and did so not for personal control, but for collective liberation. Their efforts ultimately ended in their untimely deaths but their sacrifice ultimately benefited the people they represented.
One of the most decorated military officers in U.S. history, General Smedley Butler spent his later years openly criticizing American imperialism and war profittering. He exposed a plot by wealthy elites to stage a fascist coup against Franklin Roosevelt which would have seen him put into a position of power. Rather than profit from the system he once served he spent his later years working to dismantle it.
True leadership isn't only about refusing a crown. It's more often about refusing to build a throne in the first place and choosing instead to lift others up and dismantling systems of oppression.