Slide Library in SharePoint Online

When you try to migrate from SharePoint 2010 to SharePoint Online (Office 365), Slide Library template is not listed as app in the Create App section.
You can still get it with a direct URL. I would not depend on it being there forever as the Slide Library is officially not in SharePoint 2013, but for now you can create one.
The direct URL to create the old Slide Library:

Update 22/05/2017:
Even though above solution works as expected in SharePoint 2013 & SP Online it is advisable not to use since Microsoft may remove this feature in future.