ClassPoint - ClassPoint is an all-in-one, interactive teaching tool designed to improve presenting efficiency and teaching with PowerPoint.

Slidebean - Presentations that design themselves

Embold.io - Peer Code Review

SlidesPPT - Beautiful free presentation templates for Google Slides

Graphue - Bring Your Presentations to Life With Professional Engaging Templates. Discover the best PowerPoint, Google Slides, and Keynote Presentation Templates

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.