GameObjectExtensions.cs

using System.Collections.Generic;
using UnityEngine;

namespace Unity.Extensions
{
    public static class GameObjectExtensions
    {
        public static IEnumerable<TComponent> SelectComponents<TComponent>(this IEnumerable<GameObject> source) where TComponent : Component
        {
            foreach (var go in source)
            {
                var component = go.GetComponent<TComponent>();
                if (component == null)
                    continue;

                yield return component;
            }
        }

        public static TComponent FirstOrDefaultComponent<TComponent>(this IEnumerable<GameObject> source) where TComponent : Component
        {
            foreach (var go in source)
            {
                var component = go.GetComponent<TComponent>();
                if (component == null)
                    continue;

                return component;
            }

            return default(TComponent);
        }
    }
}

public void OnDrag(PointerEventData eventData)
{
    var hoges = eventData.hovered.SelectComponents<HogeBehaviour>();
    // ...
}