Thanks for posting this. After the huge spate of religion postings last night, I went looking for the “Category Options” that used to be available, but couldn’t find it anywhere.
2 options:
1. On the forums page, right column is a list of forums. At the very bottom of that right column is a block with “Configure Sidebar”. You can select options there.
2. Under your Account >> Manage Blocks are more options. You will have to try different ones to get the list as you prefer.
[I am looking at these on a full-screen desktop IE-based browser, so your android browser may need more or different tweeking.]