Greasy Fork is available in English.

Add Keyboard Shortcut for Generic Next/Previous Page

Add CTRL+ArrowLeft and CTRL+ArrowRight for generic next/previous page. It will click the last found link/button whose text starts/ends with e.g. "Next", "Prev", "Back", or "Previous".

// ==UserScript==
// @name        Add Keyboard Shortcut for Generic Next/Previous Page
// @namespace   AddKeyboardShortcutForGenericNextPreviousPage
// @version     1.0.18
// @license     GNU AGPLv3
// @author      jcunews
// @description Add CTRL+ArrowLeft and CTRL+ArrowRight for generic next/previous page. It will click the last found link/button whose text starts/ends with e.g. "Next", "Prev", "Back", or "Previous".
// @website     https://greasyfork.org/en/users/85671-jcunews
// @include     *://*/*
// @include     *:*
// @grant       none
// ==/UserScript==

/*
The link/button text more specifically, are those which starts with (non case sesitive) "Next", "Prev", "Previous";
or ends with "Prev", "Back", "Previous", "Next". e.g. "Next", "> Next", "Next Page", "Prev", "< Prev", "< Previous", etc.
but not "< Prev Page" because the word "prev" or "previous" is not at the start/end of text.
The ID and class names are also checked.

This script doesn't take into account of links whose contents is an image rather than text, or whose text is a CSS text contents.

If next/previous navigation link is specified in the HTML metadata, it will be used as a priority.
*/

(function(rxPrev, rxNext, ts) {
  rxPrevious = /\u00ab|(\b|_)(?:back|prev(ious)?)(\b|_)/i;
  rxNext = /\u00bb|(\b|_)next(\b|_)/i;
  rxCarousel = /carousel/i;

  addEventListener("keydown", function(ev, e, a) {

    function clickLink(rx, e, i, l, r, rx2) {
      rx2 = new RegExp("[a-z].*?(" + rx.source + ")", "i");
      e = document.querySelectorAll('a,button,input[type="button"],input[type="submit"]');
      for (i = e.length - 1; i >= 0; i--) {
        if (
          (
            ((e[i].tagName === "A") && rx.test(e[i].rel) && !rx2.test(e[i].rel)) ||
            ((e[i].tagName === "A") && Array.from(e[i].classList).some(cl => rx.test(cl) && !rx2.test(cl))) ||
            ((e[i].tagName === "INPUT") && rx.test(e[i].value) && !rx2.test(e[i].value)) ||
            (rx.test(e[i].textContent) && !rx2.test(e[i].textContent)) ||
            (e[i].id && rx.test(e[i].id)) ||
            Array.from(e[i].classList).some(s => rx.test(s))
          ) && (!rxCarousel.test(e[i].className))
        ) {
          ev.preventDefault();
          e[i].click();
          return true;
        }
      }
      return false;
    }

    if (ev.ctrlKey && !ev.altKey && !ev.shiftKey) {
      a = document.activeElement;
      while (a && a.shadowRoot?.activeElement) a = a.shadowRoot.activeElement;
      if (a && ((/^(INPUT|TEXTAREA)$/).test(a.tagName) || a.isContentEditable)) return;
      switch (ev.key) {
        case "ArrowLeft": //previous
          if (e = document.querySelector('link[rel="prev"][href]')) {
            ev.preventDefault();
            location.href = e.href;
            return;
          }
          if (clickLink(rxPrevious)) return;
          break;
        case "ArrowRight": //next
          if (e = document.querySelector('link[rel="next"][href]')) {
            ev.preventDefault();
            location.href = e.href;
            return;
          }
          if (clickLink(rxNext)) return;
          break;
      }
    }
  }, true);
})();