Is there a way to prevent users from creating Documents or Whiteboards?
They aren’t tied to any database and tend to clutter the sidebar, making it harder to keep things organized. I’d love to restrict their creation or at least control visibility to avoid unnecessary mess.
Any insights would be appreciated! 
You can limit users to being Viewers for the space, and they won’t be able to create docs or whiteboards.
I need users to be able to edit a task’s status and other details, but I want to restrict them from creating new documents.
How can I limit their ability to create new docs while still allowing them to modify existing field data?
I tried setting everyone to Viewer access and then granting permissions by duplicating a template and restoring some editing abilities, but that still didn’t work.
I believe Contributor access also disallows creating docs and whiteboards, right?
Look for the Space’s sharing menu, not the database’s. So, for example, you can give people Viewer access for the Space, so that people can’t create/edit views (including docs and whiteboards). Then you can share the database with Editor access so that people can edit the entities’ details.
There are three levels of sharing: space, database and entity.
You need to share the space at Viewer level, then share databases as Editor.
You only need to play with access templates if you need sophisticated entity sharing inheritance rules.
I have the same issue,
I want to create wiki consisting of a hierarchy of Page entities.
However, user are creating documents which undermines the intended structure.
I found this post and tried your suggestion with non-admin user:
But it is still possible to create documents and everything ales as in the first screenshot.
What am I missing?
The suggestion (to make someone a space viewer but a db editor) will work to prevent them from creating Documents/Whiteboards directly in the sidebar (i.e. belonging to the space).
In the first screenshot you showed (when you have a smart folder) the user will be adding Documents/Whiteboards to the entity (not to the space) and this can’t be disabled (except by disabling all edit rights for the entity).
We do have long term plans to move away from Documents and towards a global ‘Document’ database. When this happens, it will be possible to control who can create/edit/view documents, in the same way as it is currently possible to control who can do what with any other entity.
In the meantime, we are collecting votes for a stopgap solution whereby an Admin can completely disable Documents at the workspace level.
Thanks for the clarification
Now you can disable documents creation
