Idolatry is a great abomination which G-d wants abolished or nullified, hence I want to know whether the believing people of the past took an action against it even if they were in the minority.
Are there examples, in Tanach or other traditional Jewish sources, of a prophet or his followers destroying idolatry in a majority pagan land?
There are several examples throughout Jewish literature and history. Two of the most famous are below.
One of the more famous incidents is actually not from the Torah, though it is about Avram as a young child. According to Jewish tradition, Abram's father Terah owned an idol shop, where he sold idols of all types, which he himself had made. A young Avram realized that this was wrong, and one day, when his father went out for an errand, leaving Avram to watch the shop, Avram took the opportunity to destroy all the idols except for the largest one. He took the hammer he had used to smash the idols and placed it in the hand of the remaining idol. When his father returned, he was furious and demanded an explanation. Avram insisted that the large idol had destroyed all the others, to which his father replied that this was impossible, because the idols are made of stone. To this, Avram responded that he had proven his point. But the story doesn't end there - his own father turned him over to Nimrod, a powerful warrior and leader, who led the opposition to the Monotheistic tradition that had been handed down via Noah's descendants. Nimrod had Avram thrown into a furnace, but he miraculously survived unscathed. As a result, Terah repented.
When Bnei Yisrael were enslaved in Egypt, one of the primary gods worshiped by the Egyptians was the sheep. After the 9th plague, G-d commanded us to slay a lamb and spread its blood on our doorposts as a sign, because the Plague of the Firstborns was going to commence and any home that did not have that sign would fall victim to it.
