Have you heard of the DroneKeeper Mini? If not you may want to keep it on your radar. Especially if you fly long range or over-dense ground cover. I’m writing this only based off what I have read and seen in videos because it is sold out everywhere online. But I can tell you that I definitely want to get my hands on one to test it out.
The thought is that with this device tucked into your quad and you go down in a period of stationary time an onboard battery will begin to tone, rather loudly to help you identify the location. It has an onboard LiPo so if your battery gets ejected this will still beep. It could be life or drone saver.
Here is a good video explaining how it works.