You can set custom TOC icons in Indigo HTML5 output

Indigo TOC tile icons are a bit bland, but I wrote up a post showing how you can reenable the custom TOC tile functionality that was in the initial 2017 versions of Fm and Rh.

That means you can get this:

Instead of this:

See details at 

https://techcommtools.com/custom-toc-icons-indigo/