Some airlines use disposable menus but others have a much fancier booklet, more like a restaurant menu and wine list, that is clearly collected for re-use.

The hot towels might be laundered and re-used or discarded after use.

Flowers probably won't be re-used, but ag regulations make it difficult to keep them on most routes.

Plastic silverware (cutlery) won't be reused and can be handy for cutting locally purchased fruit or cheese in one's hotel room.

Headphones/earbuds can be designed for use by a single person. Some carriers make clear whether these things are sold/given or lent/rented to passengers. Of course, the good noise cancelling equipment must be returned to the airline.