I like all different kinds of content but especially:
-gaming/some of Mark's videos where he's doing let's plays & it's a little less shouty. his voice can be incredibly soothing
-mysteries/true crime/spooky stories
-general commentary on bad films, niche subjects, etc or history
-ASMR
I'm open to new content genres though

my only rule: must be a low male voice, or at least soothing (in your opinion)
bonus: if they have an australian or british accent

youtubers i like:
markiplier (obviously, though I'm picky about what i find soothing)
Jim ASMR
The French Whisperer ASMR
Ephemeral Rift
Snooze with Sam
Aussie ASMR Man

I know a lot of thse are asmr, but I struggle with finding the right narrators for other genres.
i like That Chapter & Coffeehouse Crime but they're not voices I'd call soothing when I want to watch content but not be overstimulated.