This website is called Sparky Teaching, and it’s similar to the Two Minute Topic Talk ideas, but some of these topics require a bit more thinking and maybe even a little research.
Here are some that I think would be great writing prompts for students. Click on the images below to see the full question. You can even send your answer to the website and get it published.
Some of the questions are more like riddles:
And some focus more explicitly on language:
Anyway, there are lots of ideas to get you thinking and talking and writing in English.