Summarize A Blog Post
You can summarize your own content or a blog post by someone else.
Joel Hansen created a Twitter thread about the lessons he learned from a blog post by Sahil Bloom. He ended up getting 100000 views. You can read the case study at Indie Hackers.

What Are Your Favourite Ideas You Shared In A Blog Post?

What Blog Posts Do You Want To Write?
This can also be a great way to get feedback on potential blog post ideas.
