Modifying CKEditor toolbar at runtime We have a requirement that our standard CKEditor toolbar omit a specific button on only one content type. It seems silly to create a brand new text format just for this. I'm able to modify the toolbar via a hook, but the modification gets saved and applied everywhere.

How can I programmatically modify the toolbar for just that content type?
I think you will have to do this at the CKEditor level.  See:

https://ckeditor.com/docs/ckeditor4/latest/guide/dev_configuration.html#defining-configuration-in-page

On the Drupal side, this JS could be added by altering the content type edit form to add the JS.