Try:

list[r.nextInt(list.length)];

anyItem is a method and the System.out.println call is after your return statement so that won't compile anyway since it is unreachable.

Might want to re-write it like:

import java.util.ArrayList;
import java.util.Random;

public class Catalogue
{
    private Random randomGenerator;
    private ArrayList<Item> catalogue;

    public Catalogue()
    { 
        catalogue = new ArrayList<Item>();
        randomGenerator = new Random();
    }

    public Item anyItem()
    {
        int index = randomGenerator.nextInt(catalogue.size());
        Item item = catalogue.get(index);
        System.out.println("Managers choice this week" + item + "our recommendation to you");
        return item;
    }
}

Use the Random.nextInt(int) method:

final String[] proper_noun = {"Fred", "Jane", "Richard Nixon", "Miss America"};
Random random = new Random();
int index = random.nextInt(proper_noun.length);
System.out.println(proper_noun[index]);

This code is not completely safe: one time out of four it'll choose Richard Nixon.

To quote a documentation Random.nextInt(int):

Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive)

In your case passing an array length to the nextInt will do the trick - you'll get the random array index in the range [0; your_array.length)

rand.nextInt(10); gets a random number with no respect to the content of your list.

You need to pass the size of the list there, not literally 10 using myArray.size()

Secondly, if you want your code to do anything other than choose a random element from an empty list, you'll need to call that other method

It's a list, not an array

You don't use your randomizer object, but create a new one each time in the loop. So use the one you created (avoiding the new Random call everytime). Try:

public static void RandomSchedules(ArrayList<String[]> list)
{
    Random randomizer = new Random(System.currentTimeMillis());
    for(int i=1; i<11; i++)
    {
        String[] random = list.get(randomizer.nextInt(list.size()));
        System.out.println("Random Schedule " +  ":" + Arrays.toString(random));
    }
}

This is how to select a random element in a list:

List<String> myList = new ArrayList<>();
myList.add("M4A1");
myList.add("Kilo");
myList.add("Grau");

int randomIndex = ThreadLocalRandom.current().nextInt(myList.size());

String randomGun = myList.get(randomIndex);

The value of randomGun will be one of the three guns.

Edit:

To choose randomly a list you can create a Map of lists:

Map<Integer, List<String>> myMap = new HashMap<>();
myMap.put(1, Arrays.asList("M4A1","Kilo","Grau"));
myMap.put(2, Arrays.asList("Merc","Ranger","Commando"));
myMap.put(3, Arrays.asList("50","60","70"));

int randomIndex = ThreadLocalRandom.current().nextInt(myMap.size());

List<String> randomList =  myMap.get(randomIndex);

For a simple project is OK, but if you plan to extend this project then I recommend to use classes.