Theme filter for a view How can I theme filters for a view in drupal 8? 
I would like to place the filters to the sidebar menu, and rather than having standard either dropdown or autocomplete field, I would like to have something like a rendered block, so that a user could see all options at a glance.
Install Better Exposed Filters and if you want to have a filter as a rendered block you can edit view and see Exposed form in block: option under EXPOSED FORM. Enable it as Yes and place block in any page as you like.