Power point is a perfect way to present something visible in a digital way.
The sites listed below are the site when you can download already presentations you have to do now is to reedit it for your own use
1. PPtsearch365.com
2 Xpowerpoint.com
3. Engineeringppt.net
4. Slideshare.com
5. Authorstream.com
6. Powershow.com