I have been using the Lezyne ZECTO DRIVE MAX 400+ REAR. This thing is a killer taillight - 400 lumens that runs at 16 hours - enough for a whole day on the bike + a little extra.
Give it a look.. They have a 200 lumen version for a little less money as well.

https://ride.lezyne.com/collections/led-rear-bike-lights/products/zecto-drive-max-400-plus-rear