Front-end tools: the 2021 crowd favourites
Web Tools Weekly has again tallied the most-clicked items from its 2021 issues to produce a rundown of the front-end tools developers found most interesting during the year. The results skew toward freshly released work, so the list doubles as a preview of coming trends — from composable animation toolkits and headless UI libraries to quick-start CSS frameworks and browser-based dev utilities.
Highlights below cover everything from design tokens and UI kits to game engines, theme generators, and old-fashioned date pickers.
Tokens, frameworks and styling tools
Several 2021 favourites lean on CSS custom properties as an organising principle. Open Props offers drop-in collections of hand-crafted design tokens — animations.css, borders.css, fonts.css, zindex.css and more — or a single file that pulls everything in at once. Pollen performs a similar job as a low-level foundation for custom design systems, shipping typography, layout, UI, grid and colour modules that you can extend with your own variables.
Pico.css deliberately runs against the grain of current utility-first frameworks. It styles native HTML elements out of the box — no class soup required — with the full library coming in under 10kb minified and gzipped. Luxa CSS lands in a similar, more minimalist camp, mixing base styles with components, helpers and layout styles.
AnimXYZ describes itself as the first composable CSS animation toolkit. Instead of writing keyframes, you add classes to elements and adjust values through CSS variables, making it behave a little like Tailwind for motion work across React and Vue projects. Transition.css and Whirl round out the animation category with drop-in transition effects and a library of 100+ loading spinners, the latter grouped by pseudo-element, single-element and multi-element techniques.
Component libraries and UI kits
Tailwind-adjacent resources were a persistent theme. Tails is a drag-and-drop page builder for Tailwind projects, with two free blocks per category across 15 sections. Tail-Kit contributes a more componentised open-source set — 250+ pieces compatible with React, Vue and Angular, plus templates for dashboards, landing pages and error pages. Tailwind Components takes a directory approach, gathering community-contributed blocks under 13 categories.
On the framework side, Headless UI hit one of the fastest growth curves of the year. The library ships unstyled, accessible dropdown menus, tabs and popovers that are built to plug into Tailwind and work with both React and Vue. NextUI, a Stitches-based React library with light and dark components baked in, was an early-stage alternative for teams that want styles included. Supabase UI does similar duty for Supabase's React stack, and DevUI covers Angular at enterprise scale with components, icons, an admin template and a design system.
Two listing-style references proved useful for design-system builders. The Component Gallery collects component examples from real design systems built at eBay, Goldman Sachs, GOV.UK and others, letting you compare implementations across React, CSS, Angular and Vue. For those stuck on button design, Beautiful CSS Buttons and Buttons Generator both offer galleries of hand-finished HTML/CSS buttons you can copy directly; a third, Shaper, goes further by letting you manipulate element styling via a live interactive view and exports code using CSS custom properties.
Image, icon and colour resources
SVG Repo led the icon tools by volume with more than 300,000 free, optimised SVGs, most of them licensed for commercial work, with per-icon licence info shown up front. Iconduck is a keyword-searchable alternative carrying over 100,000 open-source icons. Snoweb's collection stands out for the animated effect built into many of the SVGs themselves.
Two pattern/texture tools appeared on the list. The Doodad Pattern Generator builds patterned backgrounds with random shuffle, category filters and full colour, transform and filter controls; exports cover JPEG, PNG, inline SVG, `.svg` and CSS background. Glitter takes a narrower brief as a text-on-glitter generator that saves as SVG — more a novelty than production tool.
Web-based image utilities include Baseline Background Remover, a free AI-powered background tool accepting JPEG and PNG files up to 5MB and returning transparent PNGs, and Frontend Toolkit's all-in-one set of more than 20 image and coding helpers. 10015 Tools operates on the same principle, bundling text, image, CSS, coding, colour and social media tools in a single dashboard.
Development and testing utilities
Prestige is a text-first HTTP client living fully in the browser: define requests in plain text, save them as a Gist, and manage cookies in an isolated space. For server-side API exploration it's a lighter alternative to Postman-style interfaces. Turbo covers the opposite base with what it calls "the speed of a single-page web application without having to write any JavaScript," bundling Turbo Drive, Frames, Streams and Native into one web-component-based library. tidy.js brings data-wrangling functions — 70+ across tidying, grouping, math and sequences — to client-side JavaScript.
HTML.cafe takes simplification to the extreme with a one-window HTML editor and live preview — no separate CSS/JS panels, since everything slots into <style> and <script> blocks. At the other end of the scale, Riju is a 224-language playground for code experiments. Closer to hand are two VS Code additions: JavaScript Booster, which surfaces refactoring actions via a light-bulb icon for JavaScript, TypeScript and React, and the Kalia and AlterNight colour themes.
Charts, animation and media-focused libraries
Charts.css fuses utility classes with chart markup: build accessible, responsive bar, line, multi-dataset and 3D bar charts in plain HTML/CSS. Vizzu targets animated charts and data stories, providing a dedicated library for building timeline-driven visualisations — one example tells you which Friends guest star had the most lines. Theatre.js takes animation in a different direction, pairing code with a visual editor suitable for DOM and WebGL animation.
The year's game engines included Kaboom, a JavaScript library with an approachable API and built-in components and events, plus Pancake, a 2D cross-platform HTML5 engine whose build step depends on Python. Party.js generated amusement with configurable confetti and sparkle particles, while Animated Backgrounds gathered CodePen demos into a video preview gallery to save your browser from loading dozens of heavyweight demos at once.
Image, colour and font collections
Skuawk offers public-domain stock photography under CC0, drawn from 16 categories across numerous photographers. colorpalettes.earth pulls colour palettes directly from Unsplash nature imagery, with new image-derived palettes arriving regularly.
Two type-related resources made the list. Coding Fonts is a quick reference for picking a programming typeface, showing sample code in HTML, CSS or JavaScript along with ligature, italic and pricing details. Uncut catalogues 90 open-source typefaces weighted toward modern and contemporary type. The Type Scale Clamp Generator built on these foundations by producing fluid type scales that rely on CSS clamp().
Static generators and low-code builders
CSS Layout Generator finished as the most-clicked tool of the year. It produces CSS and JSX for Grid-based layouts — click one of five styles and tune rows, columns, gaps, alignment and grid placement in an interactive editor, with Flexbox hinted for the future. Not far behind was UIsual, a set of eight deliberately greyscale templates that avoid lookup with pre-branded options and adapt cleanly under your own colour scheme.
Other low-code tools in the roster included Lowdefy (write YAML to produce web apps, admin panels, BI dashboards and CRUD flows), AdminJS (generate an admin UI for a Node.js back end from almost any database) and Mosaic Lite (a React/Tailwind dashboard template with optional Chart.js components, ready for SaaS products).
For a simple starting point on a plain page, HTML Boilerplates remains an adequate, toggle-driven generator, and Dopefolio fills the same niche for developer portfolios, promising SEO optimisation and strong Lighthouse scores with a live demo where you can reskin the primary colour.
Among the year's remaining clicks: MapLibre, the open-source mapping library launched in March with iOS and Android SDKs alongside JavaScript; Kaboom's higher-level sibling in the animation space; Riju's broad virtual playground; and CSS-only Generators for frosted-glass "glassmorphism" effects and interface inspiration.
