There's a great picture in a blog post called Device Fatigue. On top of all the devices in the picture, remember to add the various number of desktop monitors. Then remember that there are also a large number of browsers with new versions launched regularly.
So when you call up a website designer and ask for a website that works on all devices/browsers, please ensure you are ready to pay accordingly. Web design is cheap and easy if you don't need the website to work properly. But then so is cooking as long as no one has to eat it.