I had writing inspiration hit in a little bit different way recently and I wanted to share my experience with you!
So my brother sent me a link to an extremely popular YouTube video with literally hundreds of millions of views. I watched this thing and I couldn't believe it was so popular! But I tried to think about what made it so appealing. First of all, it targeted grade-school kids. The illustrations were very simplistic and dorky, in a funny way. It had a very catchy tune and rhyming words. It also was funny because one of the characters kept getting irritated by another nonsensical character.
Next, I tried to think about writing my own story with that same formula - dorky, rhyming, catchy, somebody getting irritated by a silly character... Well, lo and behold, I came up with a unique idea that turned out pretty good!
Most times, I read other picture books to glean ideas and inspiration, but for some reason, by looking at an animated song, I got a whole new perspective and some fresh ideas that I don't think I could have gotten in any other way.
So maybe give it a try! Find a highly viewed YouTube video targeted at the age group you write for. Watch it and try to determine why it's so popular. Then use that same formula to create your own unique story and see what you come up with!