Get all derived classes

Main.cs

public static IEnumerable<T> GetEnumerableOfType<T>(params object[] constructorArgs)
{
    return Assembly.GetAssembly(typeof (T)).GetTypes().Where(myType => myType.IsClass && !myType.IsAbstract && myType.IsSubclassOf(typeof (T))).Select(type => (T) Activator.CreateInstance(type, constructorArgs)).ToList();
}

This function can be used to get all derived classes of a parent type
usage:

public class Parent { }

public class Child1 : Parent { }

public class Child2 : Parent { }

class Program
{
    static void Main(string[] args)
    {
        var output = GetEnumerableOfType<Parent>();
        foreach (var x in output)
        {
            Console.Writeline(x.ToString());
        }
    }
    public static IEnumerable<T> GetEnumerableOfType<T>(params object[] constructorArgs)
    {
        return Assembly.GetAssembly(typeof (T)).GetTypes().Where(myType => myType.IsClass && !myType.IsAbstract && myType.IsSubclassOf(typeof (T))).Select(type => (T) Activator.CreateInstance(type, constructorArgs)).ToList();
    }
}

output:

Child1

Child2