Magento Sort Products by Attribute Set

To Sort Products by Attribute Set, Update the default toolbar files

Mage/Catalog/block/Product/List/Toolbar.php

getRequest()->getParam('attrset', 0);
        if(is_numeric($attr_set_id) && ($attr_set_id != 0)){
            $this->_collection->addFieldToFilter('attribute_set_id', $attr_set_id);
        } 
?>

in method setCollection($collection) add above code before return $this;

Now in template/catalog/product/list/toolbar.phtml file add all attribute set to select

                        getBaseUrl(), 0, -1).$url->getPath() . '?attrset=0"> Category ';

                        $entityTypeId = Mage::getModel('eav/entity')
                            ->setType('catalog_product')
                            ->getTypeId();
                        $attributeSetCollection = Mage::getModel('eav/entity_attribute_set')
                            ->getCollection()
                            ->setEntityTypeFilter($entityTypeId);

                        foreach ($attributeSetCollection as $_attributeSet) {
                            
                                if ($attrset_id == $_attributeSet->getAttributeSetId()) {
                                    $sel = 'selected="selected"';
                                } else {
                                    $sel = '';
                                }
                                echo '' . $_attributeSet->getAttributeSetName() . '';
                            
                        }
                        ?>