Provides classes that define older non-generic collections of objects, such as lists, queues, hash tables and dictionaries. Developers should prefer the generic collections in the System.Collections package.
Commonly Used Types:
System.Collections.ArrayList
System.Collections.Hashtable
System.Collections.CollectionBase
System.Collections.ReadOnlyCollectionBase
System.Collections.Stack
System.Collections.SortedList
System.Collections.DictionaryBase
System.Collections.Queue
System.Collections.Comparer
System