https://techcrunch.com/2019/12/17/need-more-buttons-for-your-ps4-controller-this-gadget-adds-two-on-the-caboose/

When you play games on your PS4, it’s fair to say that your thumbs and index fingers are generally doing most of the work. Why not put the rest of your lazy digits to work with this accessory that puts two programmable buttons on the rear of the DualShock 4 controller?

Called, imaginatively, the Back Button Attachment, the gadget plugs into the PS4’s accessory port and adds three interactive items to the back end of the controller. There are two paddle-style buttons that seem suited for middle fingers to hit easily, each of which can be programmed to be any of the ordinary buttons.