Tampermonkey script to change fonts on certain websites to Helvetica, Arial, or plain sans serif.

tm-helveticize.js

// ==UserScript==
// @name         Helveticize
// @namespace    https://flux.fm/
// @include      https://mail.google.com/mail*
// @description  Make Gmail fonts better because the suck by default.
// @author       Andrew Rechenberg
// @match        https://mail.google.com/mail*
// @match        https://calendar.google.com/calendar*
// @match        https://contacts.google.com/*
// @match        https://*.ameritrade.com/*
// @match        https://*.tdameritrade.com/*
// @match.       https://google.com/*
// @grant        GM_addStyle
// @version      20201104
// ==/UserScript==

GM_addStyle ( `

    *:not(.DPvwYc) {
        font-family:    Helvetica, arial, sans-serif !important;
    };

    .DPvwYc {
        font-family: 'Material Icons Extended';
    }
` );