Below are a list of commonly used presentation/slides websites that can be used for free. Please follow the site rules on each site for attribution as each has its own guidelines for re-using content on their sites.
KPU PowerPoint Templates
KPU branded PowerPoint templates by the Marketing department.
https://our.kpu.ca/sites/marketing/SitePages/powerpoint.aspx
PowerPoint Templates by Microsoft
Microsoft has a library of templates that you can use in your PowerPoint presentation.
https://templates.office.com/en-ca/templates-for-powerpoint
PresentationGO
Free PowerPoint library and templates.
https://www.presentationgo.com/
SlidesGo
Free Google Slides or PowerPoint presentation templates.