PlayStation 4 controller - R2 trigger has came off one of these little hinges (more detail in comments) : r/fixit
HOW TO FIX BROKEN PS4 R2 L2 TRIGGER BUTTON ON CONTROLLER - Easiest Fastest Way (no disassembly!!) - YouTube
20pairs L2 R2 Trigger Extended Buttons Kit For PS4 Controller Game Accessory
Where is the R button on a PS4 controller? - Quora
Amazon.com: eXtremeRate Black 2 Pair Custom Trigger Extenders L2 R2 Buttons for PS4 Controller, Game Improvement Adjusters for PS4 Pro Slim Controller : Video Games
R2 Button on Dualshock 4 sticking.....again. | NeoGAF
The PlayStation 4 controller: What's new with the buttons and triggers (part 3, exclusive) | Page 2 of 2 | VentureBeat
Amazon.com: eXtremeRate Clear Red 2 Pairs L2 R2 Buttons Extention Trigger for PS4 Controller, Game Improvement Adjusters Extenders for PS4 Controller JDM-030 : Video Games