In Listeo each custom field added to a taxonomy (category or region) can be also a search filter.
How to use?
First, navigate to Listeo Editor and add custom fields to categories or regions as described in article below.
Then check “add to search form” option. This will make field appear below category filter as an additional filter.
On search results page additional filters will be displayed after selecting category
P.S. If you single checkbox filter/field you can specify displayed value (by defaulty: yes), check screenshot:
