Allows you to use an entity reference field on a node to allow (or deny) access to that node to the users you have selected. Extremely useful for giving selected people access.
This isn't available in D8 or above (though it ought to be) - there's a note in the issue queue about it. #2655426
Set permissions by content type (with the option of overriding node by node)
The admin permissions page can get pretty long.
This lets you narrow it down by typing permission names into a text field.
Allows you to browse the site as another user (to see what they see) and then quickly switch back again. A general Drupal recommendation is to create test accounts for each of your roles, so this is useful for testing them. (As per notes, don't use it for anonymous access, just log out.) Replacement for 'Switch User'.
Patch and known bug: