Post it style note
A DTP program I used twenty years ago had a fantastic feature that has never been included in InDesign. At the bottom of the tools panel was a small area that when clicked and dragged off became a non-printing post-it note with the text active for immediate typing of a note.
It was really handy, as sometimes when doing a page layout you really want to note when you have say adjusted tracking, or indeed just a future reminder where for example you want to remind another designer to say edit an image etc.
Kelly Vaughn commented
While this is a nice idea, you can do this yourself with an InDesign object. Like this: https://indesignsecrets.com/nonprinting-post-it-notes-in-indesign.php