There are times that you need to know the ID number of a page or post in WordPress and it can be more painful than it should be to find that number. This plugin does one simple thing: it displays the ID number of the page, post, category, or tag you are looking at in the WordPress Admin Bar. It appends this ID to the edit menu already on the Admin Bar. Needless to say, that means that this plugin is only useful for WordPress version 3.1 or above, since the Admin Bar was first introduced with 3.1.

Admin Bar ID Menu

Makes the ID number of the current page or post visible in the Admin Bar.

KLicheR

Create a unique ID to easily identify repeater field’s rows. The field is fulfill on the first “save” of the post.
Compatibility
This ACF field type is compatible with:
<ul>
<li>ACF 5</li>
</ul>

Advanced Custom Fields: Unique ID Field

Create a unique ID to easily identify repeater field's rows.

Admin Bar ID Menu vs Advanced Custom Fields: Unique ID Field