Sketch in 3D With Animating Lines on HTML5 canvas

Spritebox – Create CSS from Sprite Images

font dragr – Drag and drop font testing

Patternizer – Stripe Pattern Generator Tool

XRAY: look beneath the skin

Automatoon- Easy Animation For The Web

HTML5 Audio element maker

SVG to HTML5 Canvas Converter

Rendera – Online HTML5 Editor

CanvasLoader Creator

HTML5 File Upload with Progress

Making a Beautiful HTML5 Portfolio

Create a Stylish Contact Form with HTML5 & CSS3

Periodic Table of the Elements

Interactive Typography Effects with HTML5

DHTMLX Touch – JavaScript Mobile Framework for HTML5 Web Apps

HTML 5 Outliner

Initializr – HTML5 templates generator

HTML 5 Demos and Examples

HTML5 Tracker

HTML 5 Visual Cheat Sheet

The HTML5 test

LimeJS – HTML5 game framework

Source: http://designmodo.com/online-html5-tools/#ixzz1mRJKtD4e