I bought a motorcycle turn signal buzzer a couple years ago from Amazon: https://www.amazon.com/Wingsmoto-Mo...304&sprefix=turn+signal+buzzer,aps,179&sr=8-7
Worked so well that it became annoying sitting at traffic lights listening to the alarm signal that sounded like a dump truck backing up. I took it off after a few months but it trained me to keep an eye on the turn signal indicators to make sure I hadn't left one on. I'm back to the original turn signal relay now.