If you have a few extra manila file folders hanging around, think about making a few of these. When working on nonfiction writing, my students love to use these research folders. The kids love that they get to take notes on 3x5 cards and write on the folder with Expo marker (very exciting for third graders!). I love that they work on breaking their research down into subtopics and organize, and reorganize their notes. Once students have their notes written and organized by topic they can easily arrange them into paragraphs by adding topic and concluding sentences.
One more easy way to use up those extra folders: Holy Cow Folders
Make 5-7 of these and have a student job (our class "Humanitarian" does this) focused on taking care of absent students. The folder goes on the absent student's desk, and the humanitarian makes sure all missed assignments, tests, and homework go inside so they're ready upon the absent kiddo's return. When a parent comes unannounced to pick up missed work, it's nice to be able to say there's a folder ready to go on their child's desk. If you want to make a little extra effort, the humanitarian can write up a note with any interesting info from the day. I haven't been able to pull this off successfully, but let me know if you do.