Questions related to Magento collections
In general, magento collections are classes that contain a list of other objects (
Varien_Data_Collection has two direct child classes,
Varien_Data_Collection_Filesystem (used to scan directories on the file system) and
Varien_Data_Collection_Db (used to load objects from the database)
The database collections are extended by
Mage_Core_Model_Resource_Db_Collection_Abstract that handles standard Magento models and
Mage_Eav_Model_Entity_Collection_Abstract that handles EAV models.