This is what i've been working on.

CSS Grid Overlay

Chrome Extension to verify grids.

Supports multiples breakpoints and the usual grid values (gutter, columns, max width, etc).

Currently has more than 15000 active users.

Available on the Chrome Webstore.

Inspect

Chrome Extension to check DOM elements distances and sizes.

The Inspect mode for any website.

Available on Chrome Webstore.

Guidelines

Chrome Extension to check visual alignments.

Available on the Chrome Webstore.

I'm a gentleman

Google Chrome Extension for easy image downloads (one click or gestures).

Around 55000 weekly active users.

More than 3.5 million monthly image downloads.

Has been used on more than 183 countries.

One of the best Chrome extensions on the webstore according to Gizmodo and The Next Web.

Available on the Chrome Webstore.

Chameleon

Dynamic theme for Firefox.

Applies the dominant color of the current page to the rest of the browser.

Available on Firefox.

Findability

Easily find and navigate through opened tabs.

Available on Firefox.

Devtools Training

App to learn about web debugging using the Chrome Devtools.

Available Online.

Learna

Playground to learn HTML/CSS/JS.

Best Open Source App at Facebook's Developer Circles 2017 hackathon.

Available Online.

What's my Disney character?

A web face filter experiment with Disney characters.

Available Online.

Hola

A little game to learn Spanish.

Uses the browser speech recognition.

Available Online.

Narrativa

A Slides App.

Automatically creates subtitles based on the transcript.

Available Online.

Cloud Copy Paste

Cloud clipboard.

Cloud clipboard that syncs between devices.

Available Online.

Tren

A Feed of cards.

Every card can load its own page.

Clicking a card shows the content in its real size.

Flexible (can accomodate different types of content).

Available on Github.

Pellizco

A javascript library that supports pinch to zoom gestures.

Weights 409 bytes minified and gzipped.

Works in Node as module (ES2015 and CJS) or in the browser (UMD).

Available on Github.

Prodigious Kombat

Mortal Kombat clone.

Made with web technologies (Javascript, Pixi.js and howler.js).

Available on Github.

FEA

An interactive playground to learn about Front End.

Available on Github.

Fittest

A lightweight Unit Testing library.

Weights 475 bytes when minified and gzipped.

Available on Github.

Atom Smart Comments

A package for the Atom editor.

Open links on comments with a single click.

Available on Github.

Vue element two-way bind

Two-way bind directive for Vue.js.

Allows two-way binding for non-input elements.

Creates the state of the app from the DOM content (no need for an API).

Available on Github.

A CSS Video

A "CSS Video" inspired by Google's: "Oct. 4" ad.

The entire 30s 1080p video can be replicated with 4.39kb of HTML/CSS/JS.

Works on any resolution without the usual compression artifacts of videos.

Available on Github.

Prodihugendavar

Theme for Hugo (static site generator).

Minimalist style focused on readability.

Responsive.

Fast (does loading, scripting, rendering and painting consistently under 10ms).

Available on Github.

EvergreenJS

Just another front-end micro-framework (using ES6/ES2015).

Zero dependencies.

Includes a router, a commonjs loader and a view template engine.

Supports only Chrome.

Available on Github.

Codex

A human friendly configuration file format (for Node).

Made for non-devs to write.

Doesn't use special characters (e.g. braces) or conventions (e.g. indentation).

Available on Github.

Available on NPM.

Vue + Express + CouchDB Todos App

Example todos app with Vue.js, Express (with Passport and Github login) and CouchDB (with Nano).

Available on Github.

Tutemet

Write TODOs fast and easy.

A "Braindump" Visual Studio Team Services Extension.

Write down all your TODOs, forget about them and enjoy your day/weekend.

Supports text auto-formatting.

Available on the Visual Studio Marketplace.

Gojira

A Jira issue search engine.

Fast results (using fuzzy search) as you type.

Support for voice commands.

Keyboard controls to ease navigation.

Add-on available on the Atlassian Marketplace. Discontinued.

Concept.

A lightweight writing app (word processor).

Winner of Intel's App Latina 2013 (best productivity app).

Automatic formatting based on context (lines that end without punctuation become titles, first letters are capitalized, etc).

Fast styling via typing (available on all keyboards, virtual o physical) and not a separate UI (writting ..italic text.. becomes italic text, etc).

Minimalistic UI that supports multiple screen and window sizes.

Designed for both keyboard and multitouch (bigger text sizes, navigation with gestures, etc).

Integration with Windows 8.1 (secondary tiles, text to speech, send document as the body of an email, share to other apps, syncing with SkyDrive, etc).

Automatic visual changes based on ambient light (when in darker rooms, the color scheme becomes darker to match the light) for improved readability.

Portability and easy publishing (documents are saved alwasys as HTML files, allowing the files to be opened with any browser).

Windows 8 App available on the Windows Store.

Typist

Experimental keyboard mini-games.

Played on more than 145 countries.

In the list of Editor's Picks of the Chrome Webstore.

Around 8000 weekly active users.

Available on the Chrome Webstore.

httpea

An iojs package that creates a simple http server for the current folder.

Inspired by python -m SimpleHTTPServer.

Uses ES 2015 features and requires no dependencies.

Available on NPM.

deletea

io.js package to delete folders and files.

Uses ES 2015 features and requires no dependencies.

Available on NPM.

daredevil

Sublime Text plugin to outline the current line.

Specially useful when cycling through search results.

Available on Github.

Glimpse

A youtube client for pcs.

Visits from more than 70 countries.

Fullscreen videos by default.

Multiple feeds with the most popular videos of the moment.

Minimalistic UI that adapts itself to the window size.

Advanced navigation and playback using the keyboard, gestures and scrolls (horizontal and vertical).

Integrated search accesible without the mouse.

Available on the Chrome Webstore.

Mases

Discover the most popular images on reddit.

So addictive that the average visit lasts more than 17 minutes.

Visitors from more than 73 countries.

Keyboard, mouse and gesture navigation.

Available on the Chrome Webstore.

Also available on the Blackberry App World (with the exclusive Built for Blackberry designation).

Web Noire

Google Chrome Extension for video downloads.

More than 5.4 million video downloads to this day.

Has been used on more than 186 countries.

Available on Github.

Hackris

Beat the computer on a fast typing competition.

Played on more than 36 countries.

Improve your typing playing against a bot.

Available on the Chrome Webstore.

Ublime

Themes for the text editors: Sublime Text, Textmate and Chrome DevTools.

Installed by more than 3200 programmers on Sublime Text.

35+ forks on Github.

Available on Github.

Astrolabe

Google Chrome Extension to switch between tabs using thumbnail screenshots.

See every page you have opened in a single screen.

To navigate to a specific tab, just click the thumbnail that shows it.

Available on the Chrome Webstore.

Available on Firefox.

Mobius

Google Chrome Extension or Javascript library that creates a minimap to easily navigate websites.

Hover the minimap (miniature copy of the page) with the mouse and the browser will go directly to that point.

Faster than the touchpad or mousewheel scroll, more precise than the scrollbar.

Extension available on the Chrome Webstore.

Library available on Github.

Newman

Google Chrome Extension that receives new mail notifications from gmail.

Get notification in the least intrusive way.

If a new mail arrived since the last time you checked gmail, the icon turn into a red paper plane. Otherwise, it's just a white sheet.

No interruptions or unread counts.

Used on more than 77 countries.

Available on the Chrome Webstore.

Google Chrome Extension that auto-expands photos, videos and conversations on Twitter.

Used on more than 73 countries.

Photos, videos and conversations (if the replies include one from the original author) appear without having to click anything.

Available on the Chrome Webstore (5/5 stars). Discontinued (twitter ui changes made the extension unnecessary).

Pale Blue Button

Google Chrome Extension that helps to save energy.

Around 140 active users.

Sleeps the computer and leaves it on energy saving mode (Windows and Mac).

Show how long you have left the computer on, idle and wasting energy.

Available on the Chrome Webstore (4.5/5 stars). Discontinued (chrome no longer support npapi plugins).

Tarnhelm

Google Chrome Extension that blocks Adsense and Google Analytics.

Around 180 active users.

Blocks a custom (black) list of domains (and optionally extensions).

Specially useful when trying to block yourself from your own websites (to avoid clicking on your own ads and counting your own visits).

Available on the Chrome Webstore.

mathematicss

A CSS Grid with variable columns in the form of a Javascript library.

730 bytes gzipped (2.54kb without minification or compression).

Available on Github.

chindogu.php

A one file MVC PHP micro framework.

The fastest and most lightweight MVC PHP Framework available (benchmarks).

Available on Github.

Debeetle

Save all console.log printed values to variables for further debugging.

Available on the Chrome Webstore.

Zemova

Javascript plugin that creates a circular (infinite) carousel.

Without dependencies or forced css styles.

Only 485 bytes gzipped (2.1kb without minification or compression).

Disponible en Github.

GĂ©neros

Men vs Women spending visualization experiment.

Motion chart that compares men and women spending.

Available on Github.

The Software T-shirt

Inspired by the Star Wars typography.

Available on Artifacts.co.

selfie

Wordpress plugin that applies the theme's CSS to the wysiwyg post editor (tinymce).

Available on Github.

lobster thermidor

Wordpress anti-spam plugin.

Available on Github.

Mobile and desktop device syncing

Real-time demo that replicates what you see in 1 device to other device(s), using node.js, socket.io and three.js.

Available on Github.

Github fork syncing script

Python script that automatically syncs your local fork with its parent repository.

Available on Github.

App Engine Sharded Counters

A Counter Library for App Engine (Python).

Available on Github.

Github pages on commit

An example setup of how to generate a Github page automtically after each commit using Travis CI.

Available on Github.

Askii

Experiments using gmail actions.

Available on Github.

Prodigious CSS Logo

A pure CSS implementation.

Available on Github.