Add video search links to your Kitsu library page for quick lookups of the shows/manga you watch/read

kitsuWatchLinks.css

.tb-watch-link {
	padding: 4px;
	border-radius: 50px;
	color: white;
	margin-left: 15px;
	margin-top: 10px;
	margin-bottom: 5px;
}

.tb-watch-links {
	margin-top: 3px;
	border-style: ridge;
	border-width: 1px;
	border-radius: 10px;
}

.tb-poster-watch-links {
	margin-left: 2px;
	margin-top: -220px;
}

kitsuWatchLinks.js

// Inject this javascript into the Kitsu library page: kitsu.io/users/*/library

// Place your links here.
//   Item 1: Name of link.
//   Item 2: Url of link.
//   (optional) Item 3: POST form parameter name
//					OR  query format updater function
const myLinks = {
	manga: [
		['Webtoons', 'https://www.webtoons.com/search?keyword='],
		['MangaRock', 'https://mangarock.com/search?q='],
		['MangaDex', 'https://mangadex.org/search?title='],
		['ReadMangaToday', 'https://www.readmng.com/search', 'query'],
		['MangaKakalot', 'https://mangakakalot.com/search/', q => q.replace(/[^a-zA-Z0-9_]+/g, '_')],
	],
	anime: [
		['CrunchyRoll', 'https://www.crunchyroll.com/search?q='],
		['Funimation', 'https://www.funimation.com/search/?q='],
		['GoGoAnime', 'https://www.gogoanime1.com/?s='],
		['9Anime', 'https://www3.9anime.to/search?keyword='],
		['OtakuStream', 'https://otakustream.unblocker.cc/?s='],
		['KissAnime', 'https://kissanime.ru/search/anime', 'keyword'],
	]
}


function findChildren(node) {
	nodes = [];
	Array.from(arguments).splice(1).forEach(name => {
		const next = Array.from(node.childNodes).find(x => x.localName === name || x.className === name);
		if(next !== undefined) {
			nodes.push(next);
			node = next;
		}
	});
	return nodes;
}

function getTooltip() {
	return document.getElementsByClassName('library-grid-popover media-tooltip ember-tether')[0];
}

function createLink(text, url, title) {
    const link = document.createElement('a');
    link.setAttribute('class', 'tb-watch-link');
    link.setAttribute('href', url + title);
    link.setAttribute('target', '_blank');
    const linkText = document.createTextNode(text);
    link.appendChild(linkText);
    return link;
}

function createPostLink(text, url, key, title) {
	const form = document.createElement('form');
	form.setAttribute('method', 'post');
	form.setAttribute('action', url);
	form.setAttribute('target', '_blank');
	const input = document.createElement('input');
	input.setAttribute('type', 'hidden');
	input.setAttribute('name', key);
	input.setAttribute('value', title);
	form.appendChild(input);
	
	const link = document.createElement('a');
	link.setAttribute('class', 'tb-watch-link');
	link.setAttribute('href', '#');
	link.setAttribute('onclick', 'return false;');
    const linkText = document.createTextNode(text);
    link.appendChild(linkText);
    link.appendChild(form);
	link.addEventListener('click', () => form.submit());
	return link;
}

function appendLinks(node, title, isPoster, isManga) {
	const links = [];
	const list = isManga ? myLinks.manga : myLinks.anime;
	list.forEach(x => {
		if(x.length === 3 && typeof x[2] === 'string') {
			links.push(createPostLink(x[0], x[1], x[2], title));
		} else {
			if(x.length === 3) {
				title = x[2](title);
			}
			links.push(createLink(x[0], x[1], title));
		}
	});
	if(isPoster) {
		links.forEach(x => x.setAttribute('class', 'grid-reaction--add'));
	}
	links.forEach(x => node.appendChild(x));
}

function createWatchLinks(isManga) {
	const table = document.getElementsByClassName('table table-responsive library-list')[0];
	if(!table) {
		return;
	}
	const [thead] = findChildren(table, 'thead');
	const [tbody] = findChildren(table, 'tbody');
	tbody.childNodes.forEach(row => {
		if(row.localName !== 'div') {
			return;
		}
		const [tr, mediaCell, cellTitle, titleWrapper, titleA] = 
			findChildren(row, 'tr', 'media-cell', 'cell-title', 'title-wrapper', 'a');
		const [entryIcons] = findChildren(cellTitle, 'entry-icons');
		const title = titleA.innerText;
		if(!findChildren(entryIcons, 'tb-watch-links').length) {
			const links = document.createElement('div');
			links.setAttribute('class', 'tb-watch-links');
			links.style.display = 'none';
			appendLinks(links, title, false, isManga);
			entryIcons.appendChild(links);
			mediaCell.addEventListener('mouseenter', () => links.style.display = 'block');
			mediaCell.addEventListener('mouseleave', () => links.style.display = 'none');
		}
	});
}

function createPosterWatchLinks(isManga) {
	const posters = document.getElementsByClassName('media-grid container')[0];
	if(!posters) {
		return;
	}
	const [row] = findChildren(posters, 'row');
	row.childNodes.forEach(poster => {
		if(poster.localName !== 'div') {
			return;
		}
		const [div1, div2, posterOverlay] = findChildren(poster, 'div', 'div', 'poster-overlay');
		const [gridReaction, gridReactionP, gridReactionA] = findChildren(posterOverlay, 'grid-reaction', 'p', 'a');
		if(gridReactionA && gridReactionA.innerText !== 'VIEW/EDIT REACTION') {
			gridReactionA.innerText = 'VIEW/EDIT REACTION';
		}
		if(!findChildren(posterOverlay, 'tb-poster-watch-links').length) {
			const links = document.createElement('div');
			links.setAttribute('class', 'tb-poster-watch-links');
			posterOverlay.appendChild(links);
			
			let enterEvent;
			const handleMouseenter = () => {
				enterEvent = setTimeout(() => {
					const tooltip = getTooltip();
					if(!tooltip) {
						handleMouseenter();
						return;
					}
					const [div3, div4, mediaTitle] = findChildren(tooltip, 'div', 'div', 'media-title');
					const title = mediaTitle.innerText;
					appendLinks(links, title, true, isManga);
					posterOverlay.removeEventListener('mouseenter', handleMouseenter);
					posterOverlay.removeEventListener('mouseleave', handleMouseleave);
				}, 50);
			};
			const handleMouseleave = () => {
				if(enterEvent !== undefined) {
					clearTimeout(enterEvent);
					enterEvent = undefined;
				}
			};
			posterOverlay.addEventListener('mouseenter', handleMouseenter);
			posterOverlay.addEventListener('mouseleave', handleMouseleave);
		}
	});
}

function run() {
	const selector = document.getElementsByClassName('ember-power-select-selected-item');
	if(!selector || selector.length !== 2) {
		return;
	}
	const isManga = selector[1].innerText.includes('Manga');
	try {
		createWatchLinks(isManga);
		createPosterWatchLinks(isManga);
	} catch(error) {
		// console.error(error);
	}
}

setInterval(run, 500);

To see how it looks, click here!