Remote switch

If I understand what you were asking for, this is called a “virtual three-way“ and any switch which is recognized by the smartthings hub can do this. The remote switch sends a message to the hub, the hub sends a message to the master switch. You just do this with the official “smart lights“ feature. Usually you do it with the option called “mirroring“ so that the status of both switches stays in sync.

There are models which are specifically designed for this, and are not wired to a load from the accessory switch. They do still require a neutral to power the radio. The following model is popular for this:

Alternatively, you can even use a battery controlled model, which literally lets you put it anywhere. See the following list. Some of these are mains powered and some are battery powered, so read the descriptions carefully. ( this is a clickable link)