Im using Robohelp 2017.
Currently, working on webhelp content, where I dont need Folder or Topic icons/images in the TOC. Unable to find solution for it.
Why not simply create a 1px x 1px transparent image and replace the relevant book/folder image file(s) for your layout with that image?
I did this for the Responsive Azure_Blue layout's toc_topic_desktop.png file, which resulted in TOC book/folder output that looks like this (What's New is a book and the Version entries are topics):
Alternatively, you might be able to get what you're looking for by creating each topic entry in the TOC as a book.
Thanks a lot. Probably this might work.