Would it be possible to add BrightSlide by BrightCarbon?
If so, BrightCarbon's support would need to be contacted to gain access to the MSI file instead of the EXE file I listed in the Download URL field. Hopefully this will be a one-time request with BrightCarbon's support.
Description from BrightCarbon's webpage:
Created for PowerPoint users on Windows and Mac, the BrightSlide add-in will help you create, polish, and edit presentations at speed. It draws on industry-standard shortcuts to boost your workflow and provides amazing, extra functionality PowerPoint users have long dreamed of. Created for our presentation designers, but shared with you, for free.
Thank you and keep up the great work!