Reveal.js - A framework for easily creating beautiful presentations using HTML
Draftsend - Presentations you can 👀 and 👂
Flowtime.js - Flowtime.js is an open source framework for easily build HTML presentations or websites.
Slidebean - Presentations that design themselves
Prezi - Welcome to Prezi, the presentation software that uses motion, zoom, and spatial relationships to bring your ideas to life and make you a great presenter.
Slides - Slides is a place for creating, presenting and sharing presentations. The Slides editor is available right in your browser. Unlike traditional presentation software, like PowerPoint, there's no need to download anything.