There are actually a surprisingly large number of games that have controller support for your mobile device. As we are seeing more console and PC ports come to mobile, I think it just makes sense that we see more controllers being sold that bring that sort of console gaming to these smaller screens.
With that in mind, recently, I've got my hands on the Serafim S3 Cloud Gaming controller, which is set up much like my Xbox controller.
One side of the controller has the D-Pad, a joystick, the options button and the other side has the X, Y, A, B buttons, a joystick, and some more options buttons. Both sides also have two sets of triggers on the top, so it does feel exactly like an Xbox controller. The Serafim S3 controller is textured on the back; however, in the box, there is a matte backing, which is slightly slimmer, that you can switch out if you do not like the texture. I found the texture grip to be good - not too much at all.
The Serafim S3 controller only works with Android devices and newer iPhones that have the USB-C connection, as you need to slot the controller into the USB-C port of your device, and then it's basically all set up. The USB-C adapter on the device isn't rigid in place, which gives some flexibility when taking your phone on and off, so that it doesn't feel like it will snap or break.
It does support a wide variety of phones, as the controller can be pulled bigger and sort of clips into whatever is placed into it. Using a phone with a case also feels like no issue, even if you have a decent-sized case, as the controller seems to be made with that in mind.
When it comes to the buttons on the controller itself, they all feel very good. Everything is raised enough, there is a satisfying push to them, and the joysticks do go back in place when you aren't touching them.
I do think the joysticks themselves feel slightly lighter than my Xbox controller, and so that's something I did very much notice, but otherwise it's quite similar. All of these buttons make a little click sound when they are pushed and are very responsive.
If you do decide to download the app, you can use some of the buttons on the controller to start taking screenshots, record gameplay, and organise games into a library that you can scroll through. The idea is to create more of a gaming console feel on your phone using this device.
It does have a subscription service for more features and use. I didn't feel this was really needed for a controller, but it's nice if you are a more serious gamer!