A small circle of billionaires, including Elon Musk and Timothy Mellon, have become notorious for pouring millions into getting former President Donald Trump elected. But according to The Washington Post, some billionaires who have been critical of Trump in the past are now keeping quiet for fear that a second, far more authoritarian Trump presidency could come after them in revenge. “With the White House appearing increasingly up for grabs, and especially as polls have tightened, numerous billionaires and other leading executives have taken steps in recent months to stay out of the race — eve…