Paste one item per line into each list. You get the overlap straight away, drawn as a Venn diagram: what’s only in the first list, only in the second, and in both. Works with three lists too.
Each line is one item. Before comparing, the tool trims extra spaces and ignores capital letters, so “Priya”, “priya” and “ Priya ” all count as the same person. Blank lines and exact repeats within one list are ignored. The version of an item shown in the diagram is the first one it saw.
The comparison runs in your browser. Your lists aren't uploaded anywhere, though they do go into the address bar if you use Copy share link, so don't share a link to a list you want to keep private.