It’s likely you are referring to the Eaton Cooper “anyplace” switch which is a zwave device and one of the first of this kind. It came out several years ago.
Now there are several from different companies, but as @gzsbado mentioned The selection does vary by country.
You can start with the following thread and that might have what you want. The Eaton Cooper is not listed there because it doesn’t at present work with the new V3 app. same with the Ecolink. But there are a few that are confirmed to work with the current platform, including the Zooz mentioned above. (The zooz is a brand new device, so probably not the one you saw before, but becoming very popular.)
Here’s the FAQ (the topic title is a clickable link)