The official Z wave alliance site lists all certified zwave products, so you can look there.
http://products.z-wavealliance.org
You do need to know what frequency you want to operate on. The SmartThings hub is currently sold on only two frequencies: US or EU. ( The frequency cannot be changed after the time of manufacture.)
Saudi Arabia uses the same frequency as the EU, which is the good news.
However, there are almost no in wall receptacles made for the EU frequency because of the variety of plug designs and wiring requirements in that region. It just hasn’t been economically viable for most companies to design.
Instead, there are two different alternatives that you will find on the list of EU certified Z wave products.
First are plug-in modules, which we usually call “pocket sockets” in this forum to make it clear what kind of devices we are talking about. There are several brands making these in various different plug formats.
Second are in wall micro modules which are wired into the circuit behind the existing receptacle. With these you have to be careful that you were getting one that can handle the amperage of the circuit. Many are really only designed for lighting and have a maximum carry load of 10 A. That’s not enough for small appliances like a blender or a hairdryer. There are heavy duty ones available, but they do cost more.
As far as zigbee goes, I don’t know what would be available in Saudi Arabia. Zigbee uses the same frequency all over the world, but manufacturers do use different profiles, so there’s not quite the same interchangeability as there is with Z wave. For example, control4 makes an excellent, if very expensive, Home automation system, but they use a proprietary encoding so that their devices don’t work with any other system.
In addition, there are regional differences on the strength of the zigbee signal that is allowed. US allows for “boosted zigbee” which transmits at almost twice the strength which is legal in the EU market. So many zigbee devices from the US cannot be used there for legal reasons even though technically they would be fine.
Zigbee is very popular for home automation in China, and there are many inexpensive devices available from there, but only a few of them have the safety certifications that are required for the EU or the US. So personally I don’t use them, although there are some community members to do.
I know that’s not really the answer you were hoping for, but there really isn’t anything that connects directly to SmartThings that matches your request.
Some UK members use the lightwave RF system for in wall receptacles but then you have to add an additional device to act as a “man in the middle” between smartthings and your lightwave RF account, and it’s not really a full-featured integration. But they do offer U.K.-style sockets.
And here’s the community thread where you can ask more about the lightwave RF option if you are interested further in that: