Whether you use PowerPoint or Keynote or Google Slides or Dextr.io, there is one clear winner as far as themes are concerned: DARK.
A Dark background with Light text. Only caveat – Don’t use Black background and/or White text. They’re far too harsh on the eye. Use dark gray and light gray instead. Alternatively you can choose darker variants of other colours like blue, brown, etc. for backgrounds. Text colours can also be yellow, cream, etc.
Avoid the opposite i.e. Light background and dark text. The worst offender is white background with black text. It hurts the eye – both aesthetically and literally.
Even better, leave the colour choices to professionals. Go here and pick any colour palette: https://colorhunt.co/palettes/dark. They all look amazing.
In On the Dark,