Terms for subject General containing class in itself

English	Russian
in a class by itself	первоклассный
in a class by itself	единственный в своём роде
in a class by itself	неповторимый
in a class by itself	неподражаемый
in a class by itself	незаменимый
in a class by itself	вне конкурса
in a class by itself	ни с чем не сравнимый