Step 1: Override the Grid.php adminhtml block (Mage_Adminhtml_Block_Catalog_Product_Grid) into local module.Assuming you have knowledge of module override.
Step2: Now add the code below in _prepareColumns() method
$attribute = Mage::getModel('eav/config')->getAttribute('catalog_product', 'designer');
$options_designer = array();
foreach( $attribute->getSource()->getAllOptions(true, true) as $option ) {
$options_designer[$option['value']] = $option['label'];
}
$this->addColumn('designer',
array(
'header'=> Mage::helper('catalog')->__('Designer'),
'width' => '80px',
'index' => 'designer',
'type' => 'options',
'options' => $options_designer,
));
Step 3: Done
Note: Assuming you have created custom product drop down attribute 'designer' with values.
Step2: Now add the code below in _prepareColumns() method
$attribute = Mage::getModel('eav/config')->getAttribute('catalog_product', 'designer');
$options_designer = array();
foreach( $attribute->getSource()->getAllOptions(true, true) as $option ) {
$options_designer[$option['value']] = $option['label'];
}
$this->addColumn('designer',
array(
'header'=> Mage::helper('catalog')->__('Designer'),
'width' => '80px',
'index' => 'designer',
'type' => 'options',
'options' => $options_designer,
));
Step 3: Done
Note: Assuming you have created custom product drop down attribute 'designer' with values.