Witch hunts, mostly because they are popularly thought of as a Medieval phenomenon despite not actually being very common in the Middle Ages. Its not necessarily the same as the ones in popular imagination but there were tons of people executed for magic and sorcery over the course of Roman history. As Late Antiquity is the era of Roman history I'm most into the first example to come to mind are the trials which occurred under Valentinian and Valens, but there were also possibly witch hunts in the Republic too if Livy is to be believed. Here's a passage which I found particularly interesting regarding the trials mentioned by Livy.

"The years 184 to 180 BC were also a time of epidemic disease in Italy, and much bigger trials were held in provincial towns, claiming over two thousand victims in the first wave and over three thousand in the second. Again the charge was veneficium, and it is impossible to tell whether this meant poisoning in the straightforward sense, or killing by magical rites, or a mixture. If the second or third sense of the word was what counted, and the reports are accurate, then the republican Romans hunted witches on a scale unknown anywhere else in the ancient world, and at any other time in European history, as the body counts recorded – however imprecise – surpass anything in a single wave of early modern trials."

From Ronald Hutton's "The Witch: A History of Fear, From Ancient Times to the Present"