These backgrounds are designed so that text, photos, and other slideshow content take center stage.
The background stays where it belongs, and you’ll create a professional-looking presentation.
FreePPTBackgrounds.net
Several ways to browse.

Freepik
Save the background only, or use the template with it already included.
Ads look like download buttons.
FreePPTBackgrounds.net is a great source for free PowerPoint backgrounds.

Freepik
Think of these downloads as a PowerPoint theme that’s broken up into separate images.
Use any image you wish.
Freepik
Fun and useful filtering options.

Huge catalog of backgrounds.
Shows similar backgrounds you might like.
Way more premium backgrounds.

Tim Oun / Unsplash
Over 6,000 additional PowerPoint background are available from this ultra-popular free image website.
PPTBackgrounds.net
Thousands of backgrounds.
Site riddled with ads.

Some images have watermarks.
PPTBackgrounds.net is another great source.
Every download page has a comment section to see what other viewers think.
you’ve got the option to also check the popularity of each background with the download counter.
Details like the size of the background and its file format are included as well.
Unsplash
Tim Oun / Unsplash
Hundreds of options.
Download in original size.
Can’t sort or filter the results.
Some images aren’t free to use.
Lots of portrait oriented photos.
Some are irrelevant for PowerPoint.
Looking for something a bit more lifelike?
Actual photos, available from thefree public domain photo siteUnsplash, are available for PowerPoint backgrounds, too.
If you need one of these images to be landscape, you cancrop the photo in PowerPoint.
Slidesgo
Unique filtering options.
Paid options mixed in.
The thousands of backgrounds at Slidesgo can be filtered by color, size, and format.
Everything else is free!