Few extension methods of IEnumerable

Following code shows few extension methods of IEnumerable<string>,

public static class EnumberableExtensions

{
         public static IEnumerable<string> IfMatchWith(this IEnumerable<string> myList, string itemToMatch)
        {
            foreach (var item in myList.Where(item => item == itemToMatch))
                yield return item;
        }
 
        public static IEnumerable<string> IfNotMatchWith(this IEnumerable<string> myList, string itemToMatch)
        {
            foreach (var item in myList.Where(item => item != itemToMatch))
                yield return item;
        }
 
        public static IEnumerable<string> IgnoreNullOrEmptyOrSpace(this IEnumerable<string> myList)
        {
            foreach (var item in myList.Where(item => !string.IsNullOrEmpty(item) && item != " "))
                yield return item;
        }
 
        public static IEnumerable<string> MakeAllUpper(this IEnumerable<string> myList)
        {
            foreach (var item in myList)
                yield return item.ToUpper();
        }
 
        public static IEnumerable<string> MakeAllLower(this IEnumerable<string> myList)
        {
            foreach (var item in myList)
                yield return item.ToLower();
        }
 
        public static IEnumerable<T> MakeAllDefault<T>(this IEnumerable<T> myList)
        {
            foreach (var item in myList)
                yield return default(T);
        }
 
        public static IEnumerable<string> IfMatchWithPattern(this IEnumerable<string> myList, string pattern)
        {
            foreach (var item in myList.Where(item => Regex.IsMatch(item, pattern)))
                yield return item;
        }
 
        public static IEnumerable<string> IfLengthEquals(this IEnumerable<string> myList, int itemLength)
        {
            foreach (var item in myList.Where(item => item.Length == itemLength))
                yield return item;
        }
 
        public static IEnumerable<string> IfLengthInRange(this IEnumerable<string> myList, int startOfRange, int endOfRange)
        {
            foreach (var item in myList.Where(item => item.Length >= startOfRange && item.Length <= endOfRange))
                yield return item;
        }
}