A bookmarketlet, that remote any query parameters starting with `utm_` from the current URL.

noutm-bookmarket.js

javascript:
(function () {
    const oldSearch = window.location.search;
    let newSearch =
        oldSearch.replace(/&?utm_[^=]*?=[^&]*?(?:&|$)/ig, "");
    if (newSearch === "?") {
        newSearch = "";
    }
    window.location.href =
        window.location.protocol + "//" +
        window.location.host +
        window.location.pathname +
        window.location.hash +
        newSearch;
})();