Geizhals filter price info - unfinished (but working) script to get an easier overview of prices for filters in geizhals

gh-filter-price-info.user.js

// ==UserScript==
// @name         Geizhals filter price info
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  display price info on geizhals filters
// @author       You
// @match        https://geizhals.de/?*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=geizhals.de
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    let price_list = [];
    document.querySelectorAll('div.cell.productlist__price').forEach((e) => { price_list.push(e.innerText); });
    window.localStorage.setItem(window.location.href.split('/').at(-1), JSON.stringify(price_list));

    let preloading = window.localStorage.getItem('preloading');
    if (preloading) {
        preloading = JSON.parse(preloading);
    }
    try {
        if (preloading && preloading.length > 0) {
            let preloading_url = preloading[0].split('/').at(-1).replace(/%E4/i, "ä").replace(/%F6/i, "ö").replace(/%DF/i, "ß");
            let own_url = window.location.href.split('/').at(-1).replace(/%E4/i, "ä").replace(/%F6/i, "ö").replace(/%DF/i, "ß");
            if (decodeURIComponent(preloading_url) == decodeURIComponent(own_url)) {
                preloading.splice(0, 1);
                window.localStorage.setItem('preloading', JSON.stringify(preloading));
                if (preloading.length > 0) {
                    window.location.href = preloading[0];
                } else {
                    window.close();
                }
            }
        }
    } catch (err) {
        console.log(preloading[0].split('/').at(-1), window.location.href.split('/').at(-1));
        console.log(err);
    }

    document.querySelectorAll('a.xf_i').forEach((e) => {
        let price_list = window.localStorage.getItem(e.href.split('/').at(-1));
        if (price_list && price_list.length > 0) {
            let elem = document.createElement('span');
            elem.innerHTML = JSON.parse(price_list)[0];
            elem.classList.add('xf_n');
            e.appendChild(elem);
        }
    });

    document.querySelectorAll('ul.filterbox__list>li.filterbox__list__item.fltrs_searchterm').forEach((e) => {
        let urls = [];
        document.querySelectorAll('a.xf_i').forEach((el) => {
            urls.push(el.href);
        });
        let elem = document.createElement('a');
        elem.innerHTML = 'preload all';
        elem.onclick = function (urls) {
            return function () {
                window.localStorage.setItem('preloading', JSON.stringify(urls));
                window.open(urls[0]);
            };
        } (urls);
        e.appendChild(document.createElement('br'));
        e.appendChild(elem);
    });

    document.querySelectorAll('ul.filterbox__list>li.filterbox__list__item.fltrs_searchterm').forEach((e) => {
        let urls = [];
        document.querySelectorAll('a.xf_i.xf_sel.xf_esel').forEach((el) => {
            urls.push(el.href);
        });
        let elem = document.createElement('a');
        elem.innerHTML = 'preload selected';
        elem.onclick = function (urls) {
            return function () {
                window.localStorage.setItem('preloading', JSON.stringify(urls));
                window.open(urls[0]);
            };
        } (urls);
        e.appendChild(document.createElement('br'));
        e.appendChild(elem);
    });

    document.querySelectorAll('th.xf_th').forEach((e) => {
        let urls = [];
        e.nextSibling.querySelectorAll('a.xf_i').forEach((el) => {
            urls.push(el.href);
        });
        let elem = document.createElement('a');
        elem.innerHTML = 'preload';
        elem.onclick = function (urls) {
            return function () {
                window.localStorage.setItem('preloading', JSON.stringify(urls));
                window.open(urls[0]);
            };
        } (urls);
        e.appendChild(document.createElement('br'));
        e.appendChild(elem);
    });

})();

Collects data from open tabs and inserts a "preload" button to open (and close) an entire row in tabs (you still need to reload your original page though).

Added "preload all" and "preload selected" buttons.