There are basically four different types of generic collections which are as follows:-

1. List:-Lists are indexed based Generic Collections. Lists are Generic form of ArrayList.

List helps us to create flexible strong type collection as you can see in below code snippet i have defined List as "int" and "string".

//index based Generic collection            
List<int> ObjInt = new List<int>();         
ObjInt.Add(123);            
ObjInt.Add(456);            
Console.WriteLine(ObjInt[0]); //accessing the List by internal index based value.            
List<string> ObjString = new List<string>();            
ObjString.Add("feroz");

2. Dictionary:-Dictionary are key based generics collection.
                     Dictionary are generic form of Hashtable.

 //key based Generic collection            
Dictionary<int, int> ObjDict = new Dictionary<int,int>();            
ObjDict.Add(1,2);            
Dictionary<int, string> ObjDict1 = new Dictionary<int,string>();            
ObjDict1.Add(3, "feroz is a developer");            
ObjDict1.Add(4, "wasim is a developer");            
Console.WriteLine(ObjDict1[3]); //accessing the dictionary by defined key.

3. Stack:-Stack generic collection allows you to get value in "LIFO"(last in first out) manner.

// Stack             
Stack<string> ObjStack = new Stack<string>();            
ObjStack.Push("feroz");            
ObjStack.Push("moosa");            
Console.WriteLine(ObjStack.Pop());

4. Queue:-Queue generic collection allows you to get value in "FIFO"(first in first out) manner.

//Queue            
Queue<int> ObjStr = new Queue<int>();            
ObjStr.Enqueue(789);            
ObjStr.Enqueue(456);            
Console.WriteLine(ObjStr.Dequeue());

For more information about generic, please watch the below video.