Mr Baz is a good one!
EDIT:
I just mentioned the one for the batteries and chargers. Other member are already pointing out some other channels. Still, here are some contributions (besides the ones being mentioned):
- Living Survival - Living Survival - YouTube
- Zozzlights (aka Zozz) - Zozzlights RC - YouTube
- WeAllJuggleKnives - WeAllJuggleKnives - YouTube
- ThatCrazyFlashaholic 67 (aka Brainsick67) - ThatCrazyRCGuy67 - YouTube
- Room X - roomX - doorman's channel - YouTube
- Bushcraft412 - Bushcraft412 - YouTube
- jojoselected (German) - jojoselected - YouTube
- Jon M (aka liquidretro) - LiquidRetro - YouTube
- LumenReviews (aka Budda) - LumenReviews - YouTube
And this is a similar thread from sometime ago: your fav flashlight youtube reviewer?