I have been looking a way to get all the layered navigation filters available, i dont know if this is per category or if i cant get all of them, because i need them on the admin side to choose in each category which ones i want to use, but currently i have been just able to get them in the front end when a category is selected by this line:
$appliedFilters = Mage::getSingleton('Mage_Catalog_Block_Layer_State')->getActiveFilters();
Best Answer
If you simply want to get all attributes that are set as filterable via the admin section then you need to filter on the table
catalog_eav_attribute
where the columnis_filterable
is true: