System.Linq

 namespace System.Linq {
     public static class Enumerable {
-        public static IEnumerable<ValueTuple<TFirst, TSecond>> Zip<TFirst, TSecond>(this IEnumerable<TFirst> first, IEnumerable<TSecond> second);

     }
     public static class Queryable {
-        public static IQueryable<ValueTuple<TFirst, TSecond>> Zip<TFirst, TSecond>(this IQueryable<TFirst> source1, IEnumerable<TSecond> source2);

     }
 }