So you are trying to see if a student has opened a document you shared or created with them right?
I am a Google Slides fangirl. I use it for everything when I am teaching from created hyperdocs (more about them later), posters, stickers, and so much more. Slides is more than it appears to be.
If you know me at all you know I love Bitmojis. They are such a fun online sticker for education. During this trying time adding a bitmoji or two to a students assignment or adding them to my own assignments just gives my assignments a bit of flair. So much so that I created a virtual library a couple of weeks ago.