Related Categories - Related Searches

I’m looking for way to add a related categories section on my search results page.

So let’s say the user searches for:

  • iPhone

At the bottom of the search results I’d like to have links to other related categories like:

  • Smartphones
  • Laptops
  • Apple
  • Tablets

All these categories are categories assigned to the items in my index.

Could anyone point me in the right direction?