I use this editable Google Slides graphic organizer with my middle school ELA students to help them create and prove thematic statements before extending their thoughts into a longer paragraph.  To have students use this resource, you will need to make a copy and share it. 

Click here to access the editable graphic organizer. If you make a copy for students in Google Classroom, they can type directly into the document. Alternatively, you can print the graphic organizer for student use.

This is a small aspect of a series of resources I use to teach theme. Unfortunately, I cannot link my full lesson because it incorporates others' resources, and I don't yet have permission to post them. I strongly recommend that you first teach your students how to find theme with one or more mini-lessons and whole-class examples, using this graphic organizer as a resource once they understand the basic concept of theme. Generally, we complete at least one graphic organizer together, then we complete another in groups or partners before students try this on their own.

You can also choose to have students write a single topic in the brainstorm bubble instead of multiple topics. When we first practice this, I choose a topic for the class to work with together. Students move to brainstorming their own topics once I am confident that they understand the concept of theme.