Selectable.allSelectables

Description

List of all the selectable objects currently active in the Scene.

Selectable.allSelectables.

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // required when using UI elements in scripts

public class Example : MonoBehaviour
{
    //Displays the names of all selectable elements in the Scene
    public void GetNames()
    {
        foreach (Selectable selectableUI in Selectable.allSelectables)
        {
            Debug.Log(selectableUI.name);
        }
    }
}