Free alternative to PowerPoint.
With ‘Presentation PowerPoint’ you can view PowerPoint presentations even with no MS Office installed.

Presentations can be exported to images.
Presentations can be exported to video mp4 (pro version)
Works for PowerPoint presentations done with
PowerPoint 2007 - 2016.
Earlier versions of PowerPoint (.ppt) files are not supported.

Features:
View PowerPoint
Convert PowerPoint to image.
The full version supports full screen

This is the free version. There is also a pro version of this app here: https://www.microsoft.com/en-us/p/presentation-pptx/9nwkb9zb2t7z