Linq for Unity Vector3.

Vector3Extension.cs

using UnityEngine;
using System.Collections.Generic;
using System.Linq;

namespace AppKit.Extension
{
    public static class Vector3Extension
    {
        public static Vector3 Average(this IEnumerable<Vector3> source)
        {
            int length = source.Count();
            Vector3 all = Vector3.zero;
            foreach(Vector3 v in source)
            {
                all += v;
            }
            return all / length;
        }
    }
}