+1 for the cygolight tail light, love mine. Best under $30 ive spent on a tail light. I use a rack mount with it.

I run a more expensive light because my commuting/pavement etc bike gets rained on and such, dont trust pack waterproofing. Have a case for 18650s that works good too, but I've gotten pretty attached to my fenix bc30r. With having probably 10 USB chargers around my house I can just plug it into closest one. Or charge at work if needed. Also unlike the old mj808 clone, I dont get pissed off drivers due to the blinding glare. And its on a slide mount stock.

My trail bike on the other hand, whole different story. Lights were cheaper and put out more light. I dont buy lights off amazon anymore only because 99% of the cheaper lights are all cool white and i went over to the neutral white. Sadly all have the band mounts, even the ones I have, so ordered custom gopro adapters.