While PowerPoint does not have a Timelines category within the SmartArt graphics available, you can still find some Timeline variants hidden within the Process category.
To learn more, choose your version of PowerPoint. If we do not have a tutorial for your version of PowerPoint, explore the version closest to the one you use.
Microsoft Windows
Creating Timelines Using SmartArt in PowerPoint 365 for Windows
Tutorial Code: 11 03 08
Previous: 11 03 07 Add Office.com SmartArt Graphics
Next: 11 03 09 Get More SmartArt Graphics