Text cleanup tools that respond as you type: counting, case conversion, sorting, de-duplication and diffing, plus the Invisible Character Detector for the day a string 'looks identical but doesn't match'.
These are deliberately instant, no buttons where live output is possible, and nothing you paste leaves the page, which matters when the text is a customer list or a contract draft.
For cleaning up an export, the order saves re-work. Strip the whitespace first so that lines which differ only by a trailing space stop counting as different, then remove duplicates, then sort, and do any find and replace last, once the list is stable. If two strings still refuse to match after all that, the Invisible Character Detector is the one that finds the reason, and it is almost always a zero-width space that came in with a web copy.