Formal:
* Вы замечательные (Vy zamechatel'nye) - This is the most formal way to say "you are wonderful" and is appropriate for addressing someone with respect.
* Вы прекрасны (Vy prekrasny) - This is also quite formal and emphasizes the beauty or excellence of the person.
Informal:
* Вы отличные (Vy otlichnye) - This is a more casual way to say "you are wonderful" and is suitable for friends or people you know well.
* Вы классные (Vy klassnye) - This is very informal and means "you are cool" or "you are awesome."
* Вы замечательные (Vy zamechatel'nye) - This is also informal and emphasizes the person's good qualities.
To describe something as wonderful:
* Это замечательно (Eto zamechatel'no) - This means "this is wonderful" and can be used for anything.
* Это прекрасно (Eto prekrasno) - This means "this is beautiful" or "this is excellent" and is often used for things that are aesthetically pleasing.
* Это отлично (Eto otlichno) - This means "this is great" or "this is fantastic" and is a more informal way to say "this is wonderful."
Remember that the best way to say "are wonderful" in Russian will depend on the specific context.