Thanks to Richard Byrne, I learned that there’s a function at the TED-Ed site that lets you search lessons by grade-level. Click on “students” and you can see in the above screenshot what it shows.
To tell you the truth, I’m not really sure how useful it is since it appears, after a quick look, like many of the lessons are in all grade-levels. But I’m sure there is some separation. It could be helpful if you don’t have much time and what to quickly search.
I’m adding this post to The Best Teacher Resources For “TED Talks” (& Similar Presentations).