Which of the following applications does not support add-ons?

Slides does not support add-ons, which distinguishes it from the other applications listed. Add-ons are third-party applications that enhance the functionality of Google Workspace tools by integrating additional features and capabilities.

In the case of Sheets, Docs, and Forms, these applications can effectively utilize add-ons to extend their functionalities. For example, a user can add advanced data manipulation tools in Sheets or incorporate new features that streamline document editing in Docs. Forms can also benefit from add-ons that help in survey distribution or data collection.

Slides, while it may offer various built-in features for creating presentations, does not have the same range of third-party integrations available through add-ons as the other applications. Understanding the functionalities and limitations of these Google Workspace applications can be vital for effectively utilizing them in various projects.