8BitDo Mobile Gaming Clip

Well-designed and surprisingly sturdy. If you're looking to use the controller with a mobile phone, this is highly recommended.

The clip also has a lot of small details so it should fit most, if not all, phones. There's two level grooves on the rubber pads that hold the phone so if holding you're phone in the middle/centre of mass means the grip goes over the power button, shouldn't be too big of an issue. For some context, my phone is a Poco X6 Pro (Global) so the clip needs to go over the power button for a balanced grip.

The clip said it would fit my controller and it didn't. :c