The DependencyInjection component allows you to standardize and centralize the way objects are constructed in your application.
The VarDumper component provides mechanisms for walking through any arbitrary PHP variable. It provides a better dump() function that you can use instead of var_dump().
Inflector converts words between their singular and plural forms (English only).
The PropertyAccess component provides function to read and write from/to an object or array using a simple string notation.
PropertyInfo extracts information about PHP class' properties using metadata of popular sources.
With the Serializer component it's possible to handle serializing data structures, including object graphs, into array structures or other formats like XML and JSON. It can also handle deserializing XML and JSON back to object graphs.
A set of abstractions extracted out of the Symfony components