PowerPoint: Themes and Templates
Start with a theme that is already accessible. Not all of the built-in themes have high enough contrast or large enough font. Make it easier to create an accessible presentation by starting out with a theme that is accessible.
You may select the theme from the Design tab or search for a template or theme by selecting File > New and then searching.
Add accessibility to your search query for themes tagged as accessible.
Microsoft has identified a few templates for accessibility.