Different generic collections defined in System.Collections.Generic Namespace are listed below :

1. List<T> – Represents a strongly typed list of objects that can be accessed by index.
2. Dictionary<TKey, TValue> – Represents a collection of keys and values
3. HashSet< T> – Represents a set of values.
4. LinkedList< T> – Represents a doubly linked list.
5. Queue<T> – Represents a first-in, first-out collection of objects.
6. Stack<T> – Represents a variable size last-in-first-out (LIFO) collection of instances of the same arbitrary type.
7. SortedDictionary<TKey, TValue> – Represents a collection of key/value pairs that are sorted on the key
8. SortedList<TKey, TValue> –Represents a collection of key/value pairs that are sorted by key
9. SortedSet<T> – Represents a collection of objects that is maintained in sorted order.