Content creation is probably one of the toughest aspects about being a blogger. And when you have a service like Patreon, that's considered a blog too. After all, you post content for the public or just for your patrons to read.
While free or Patreon-only stories are always a hit with your supporters, so too are sneak peeks, behind the scenes writing, as well as a general update. Are there any lines or scenes that you wrote that really tickled your fancy? Did you just read a book and found yourself inspired? For those who research, what nifty nonfiction books have you read? (I'm a bit of a geek that way and LOVE to know bibliography-wise what research materials people used.)
If you're not regularly or consistently posting on your Patreon, you can look at your interactions to see what posts got the most comments and the most views. Use this as your guide as to what to post.
If you haven't yet started, think about the things you read that you enjoy on author blogs.
And finally, it doesn't hurt to experiment with different types of posts and information. Not everyone enjoys reading the same things and the reader who enjoys reading about your research may not care about your updates or your funny cat stories. (Gasp! The horror, I know!)
The important part is that you don't treat it like a chore, but rather one of the many ways you interact with readers. So what are you going to post today?