Code Bucket …

using System;
using System.Collections.Generic;

namespace Incah.Core
{
	public static class ListExtensions
	{
		public static IEnumerable<T> Reversed<T>(this List<T> list)
		{
			for (int index = list.Count - 1; index >= 0; --index)
				yield return list[index];
		}

		public static T GetNormalized<T>(this List<T> list, int index)
		{
			return (index %= list.Count) < 0
				? list[list.Count + index]
				: list[index];
		}

		public static T GetNextItem<T>(this List<T> list, T item)
		{
			int index = list.IndexOf(item) + 1;
			return list.GetNormalized(index);
		}

		public static T GetPreviousItem<T>(this List<T> list, T item)
		{
			int index = Math.Max(0, list.IndexOf(item)) - 1;
			return list.GetNormalized(index);
		}

		public static IEnumerable<F> Find<F, T>(this List<T> list)
		{
			foreach (object value in list)
			{
				if (value is F)
					yield return (F)value;
			}
		}

		public static IEnumerable<F> Find<F, T>(this List<T> list, Predicate<F> predicate)
		{
			foreach (F value in list.Find<F, T>())
			{
				if (predicate(value))
					yield return value;
			}
		}

		public static IEnumerable<F> Find<F, T>(this List<T> list, Func<F, bool> predicate)
		{
			foreach (F value in list.Find<F, T>())
			{
				if (predicate(value))
					yield return value;
			}
		}
	}
}