Making and reorganizing boards is something that would need to be done at a modly level, so unfortunately you wouldn't be able to do that. Did you have something specific in mind? There's a chance there may already be a board or thread relevant to what you're wanting to make that we can help find.
Splatterboard is the catch-all board for random topics that don't fit anywhere else. Our dedicated space to "talk about whatever" is the "'bloid" thread.
If you're looking to gather ideas on a specific topic or for a project, I suggest creating your own thread for it on a fitting board. It'll catch more attention as its own separate thread than it would within a general chat topic, and will be much easier to keep track of everything posted.
The creative endeavours boards are for sharing your works (or the Neopets' boards for Neopets-related works). Alternatively, you can also post about your own works and personal projects in a journal-style topic on Dear Diary.