Ease is described as 'modern desktop presentation application for GNOME, with Clutter-based visuals' and is a presentation maker in the office & productivity category. There are more than 25 alternatives to Ease for a variety of platforms, including Online / Web-based, Mac, Windows, Linux and iPad. The best alternative is LibreOffice - Impress, which is both free and Open Source. Other great apps like Ease are Google Slides, Microsoft Powerpoint, Sozi and Keynote.
Ease is mainly a Presentation Maker but alternatives to it may also be Slideshow Makers. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Ease.
We are Ludus, making a slides builder for creatives. We are mixing pro features from Sketch, with the power of internet (Sketchfab, Framer, CodePen ... are some of our integrations). So slides can be truly creative and limitless.
Takes a few hours to catch on, but makes the most professionally typset documents with a large number of amazingly useful features not available from other types of presentation software. For presentations, consider the Beamer or Prosper document class.