When you think about how to plan the content for your Patreon, or even just a blog, everyone has their own method. Some, like me, prefer spreadsheets. Others use a calendar, whether that's a wall calendar with a white board or just a printed out calendar that they write on. Have you thought to look in the school supply aisle?
Where I live, since school has been back in session for about two weeks and Halloween items are going on the shelves, the school supplies are moving to clearance and that means you can pick up options for content planning relatively cheap. One that I've used is an assignment book.
This is a small notebook that you can use to choose blog topics by day, by week, or any way you'd like to. I've seen these little books on clearance for a buck or two, and it means that if you have yet