What tools allow for creation and editing of a PDF document on OS X? I would like to create a PDF document with images, text and table of contents.
I have also other PDF documents that I would like to merge in this new PDF.

Do you know some tools/software for creating PDFs?
You can actually merge multiple PDFs right from Preview.app. Just open two PDFs in two separate windows, turn on the sidebars, and drag pages from one sidebar to the other. This won't provide you with a table of contents, but you can always just make something in TextEdit, export it as a PDF, then add it to the beginning of the document.