In that latter category I’m going to suggest the magnificently monickered John Law
Born in Scotland to a middlingly wealthy family of goldsmiths, he left Edinburgh for London where he took to gambling his income from his share in the family business - successfully. Took his mother to court to maintain access to funds, she having cut him off.
Killed a man in a duel over a lady’s honour. Sentenced to death,.escaped jail, fled to the Netherlands. Probably with the connivance of the King.
Wrote treaties on fiat money and financialisation of state debt. Gambled and speculated successfully in the Dutch and Genoese markets. Gradually moved in more and more respectable circles until he came to the notice of Phillipe Duc D’Orleans, Prince-Regent of France.
Moved to Paris, correctly observed that the French economy was run on lines that were both inefficient and lunatic. Came up with rationalising system that in some ways anticipated reforms that wouldn’t otherwise be seen till the Revolution, in some ways copied from and in turn inspired the financial revolution in England/Britain which would go on to make that country a world power.
Gave the French economy a rocket boost, diverted capital from buying state sinecures into actually productive industry, took over France’s few and anemic trading concessions. Which trade included slaves. Nationalised state debt. Founded the Missisippi Company to colonise the mouth of the Mississippi, including a city named after his patron, the Duc D’Orleans. Became the richest man in France. Gets mixed up with the Jacobites in ways that do neither him nor them any good.
The controversial bit: depending on who you believe, the next bit happened either because Law was a get rich quick schemer who screwed over a whole nation and wriggled away; or a visionary whose ideas were sound brought low by nothing worse than bad luck - with a few more months all would have come good.
The Mississippi Company draws enormous amounts of speculation, shares inflate well past any possible valuation, then ineveitably slide. Despite various (cynical? half-hearted?) efforts, there is a crash similar to but even more devastating that the South Sea Bubble. The cause of French financial reform is irretrievable tarnished, and its basket case ways continue until, and largely cause, the French Revolution. Laws escapes to Venice, apparently penniless but pursued by rumours that he has secreted vast funds away somewhere. Ends his days gambling and being spied on by at least five different factions.
The ship carrying his bequests to his family runs aground, all cargo lost. No one ever finds out exactly what and how much he left them.