I have installed Magento 18.104.22.168, in which I have not written a single line of code there and not any custom or third party module installed there.
I have just created few categories and products at backend.
When I go category page (product listing page) at forntend, filter are not visible there below category filter.
There is an attribute color, I have assigned it on products.
But this attribute is not visible at frontend. Below are the things which I have checked double and sure about --
1) I have assigned color attribute to Default attribute set.
2) color attribute has
Use In Layered Navigation option set to
Filterable (with result)
3) Have cleared