Dim x As New List(Of Integer)
Dim y As New List(Of Integer)
 
x.Add(1)
x.Add(2)
x.Add(3)
 
y.Add(3)
y.Add(4)
 
Dim z1 As List(Of Integer) = (x.Union(y)).ToList     '-->  1,2,3,4
Dim z2 As List(Of Integer) = (x.Concat(y)).ToList    '-->  1,2,3,3,4
Dim z3 As List(Of Integer) = (x.Intersect(y)).ToList '-->  3
Dim z4 As List(Of Integer) = (x.Except(y)).ToList    '-->  1,2