I have the following, which I didn't make myself

DontF-withPaste

javascript:forceBrowserDefault=(e=>{e.stopImmediatePropagation();return true;});['copy','cut','paste'].forEach(e=>document.addEventListener(e,forceBrowserDefault,true));

Purpose: Restore the ability to paste stuff anywhere, some websites will do this in their password field

kill-sticky

(avascript:(function(){document.querySelectorAll("body *").forEach(function(node){if(["fixed","sticky"].includes(getComputedStyle(node).position)){node.parentNode.removeChild(node)}});document.querySelectorAll("html *").forEach(function(node){var s=getComputedStyle(node);if("hidden"===s["overflow"]){node.style["overflow"]="visible"}if("hidden"===s["overflow-x"]){node.style["overflow-x"]="visible"}if("hidden"===s["overflow-y"]){node.style["overflow-y"]="visible"}});var htmlNode=document.querySelector("html");htmlNode.style["overflow"]="visible";htmlNode.style["overflow-x"]="visible";htmlNode.style["overflow-y"]="visible"})();

Purpose: Un-stick anything that remain static when you scroll, ex: website header

I have this to open the site in archive.today:

javascript:void(open('http://archive.today/?run=1&url='+encodeURIComponent(document.location)))

I've been using this guy's one for years. It's called stretch video

https://gist.github.com/arpruss/74abc1bc95ae08e543b9b74f15a23b07

It's not often I have to use it but if you ever watch something online where the uploader has messed up the aspect ratio you can just fix it just like that, no need to download and reencode or anything I love it.

https://naich.net/useful/

There's a couple there - one changes password fields to text and the other unchecks all the boxes on a page.

I wrote this one ages ago to throw shopgoodwill.com items in my calendar because the times are in PDT and they don't have any built in notification (that works)

Also made it work with govdeals but I haven't tested that in ages so YMMV

Writes it to a Google calendar URL. I had it write to an ICS file at one point but I don't have version control on this one file

javascript: (
    () => {
        function createItem(productTitle, date) {
            console.log(productTitle, date);
             window.open(`https://calendar.google.com/calendar/render?action=TEMPLATE&text=${productTitle}&details=${productTitle} @ Goodwill ${window.location}&dates=${date}/${date}`);
        }
        if (window.location.href.toString().includes("https://shopgoodwill.com/item/")) {
            try {
                let title = document.querySelectorAll(".mb-4.d-none.d-md-block.ng-star-inserted")[0].innerText;
                let headers = document.querySelectorAll("th.font-weight-bold.text-nowrap");
                let time;
                if (headers[4].innerHTML == " Handling Price: ") {
                    time = headers[5] }
                else {
                    time = headers[4]
                }
                time = time.parentElement.children[1].innerHTML.substring(0, 25) + "DT";
                console.log(headers);
                createItem(title, new Date(time).toISOString().split(".")[0].replace(/-/gi, "").replace(/:/gi, "") + "Z");
            } catch (e) {
                alert("An error occurred, check the console for full details: " + e);
                console.log(e); 
            }
        } else if (window.location.href.toString().includes("https://www.govdeals.com/index.cfm")) {
            try {
                createItem(document.querySelectorAll("#asset_short_desc_id")[0].innerText, new Date(document.querySelectorAll("tr > td[align='right'][nowrap='nowrap'] > b")[0].innerText.replace("ET", "EDT")).toISOString().split(".")[0].replace(/-/gi, "").replace(/:/gi, "") + "Z");
            } catch (e) {
                alert("An error occurred, check the console for full details: " + e);
                console.log(e);
            }
        } else {
            alert("This is not a goodwill or govdeals item page.");
        }
    })();

I wrote this one to strip the custom css from any sub on (old) reddit. I use it on subs I find annoying, like mildlyinfuriating.

javascript:(function(){x=0;s=document.styleSheets;for(const y of s){if(y.title==="applied_subreddit_stylesheet"){if(y.disabled!=true){y.disabled=true;}else{y.disabled=false;}}x++;}})();

Export a table to csv

https://github.com/zarinlo/export-html-table-bookmarklet

I used to use Power Delete Suite to nuke Reddit comments.

I should give it a look

I dont see any use and usage mentioned there is useless