This is gross historical illiteracy. The Populists were a highly specific movement of agrarian socialists that arose in the United States, first in the Farmers Alliances, later becoming a political party, the Populist Party, at the end of the nineteenth century.
The Populist were, again socialists, agrarian socialists. Their platform is readily available on line for anyone who would be informed, rather than blathering on and perpetuating the common misuse of the term.
As a political party, the Populists were not hugely successful. The entered into a “fusion” ticket with the Democrats in nominating William Jennings Bryan for president in 1896. Bryan lost to William McKinley.
Despite their political failure, the Populists were remarkably successful in policy terms. By the end of the Great Depression, nearly their entire policy program was federal law. They demanded a uniform national currency in sufficient quantity to facilitate transactions (this was actually a problem at the time). It is now a subject of considerable controversy, but the Federal Reserve was a progressive reform at the time of its creation.
They called for reform in the conduct of elections, which was a major focus of Progressive Era reformers, including the introduction of the secret ballot. The Populists favored the initiative and referendum as mechanisms to allow the voting public to play a more direct role in governing, and several states that joined the Union in the late nineteenth century incorporated them into their state constitutions.
The Populists wanted a progressive income tax, which we enabled with the sixteenth amendment to the Constitution. They demanded direct election of Senators, which we instituted with the seventeenth amendment to the Constitution.
They called for government warehouses to store grain as a mechanism to help farmers deal with the vagaries of prices in agricultural commodities. What we actually have instead is functionally the same, federal crop insurance, a huge program that provides large sums annually to farmers.
A major demand that never came to pass was public ownership of railroads, meaning freight rail, since transporting their crops to market was a major concern for farmers all over the country.
The Populists were opposed to immigration and called for limits on it, which had already begun in 1882 with the Chinese Exclusion Act.
It is pointless to ask what Trump would have thought about any of these policies because Trump does not think about policy. They do, taken together, add up to a form of socialism, again, agrarian, which Trump claims to oppose. The one point on which Trump might agree with the Populists is in his opposition to immigration.
To refer to Trump, or any European political movement, as “populist” is only to prove how grossly ill informed you are. Use Google. You’ll like it.