I need to have an overview of all created Nintex Forms and Workflows.
Is there a way to get such a list?
The answers are on this community.
Finding all of the workflows in your farm using PowerShell
Locate Nintex Forms in SharePoint via PowerShell
Hope it helps.
PowerShell is your friend
You can see with the user interface, via the "Site Settings" > "Workflow gallery" all the workflow that are used in a site but it is for a site and workflow only.
Retrieving data ...