Outside of kids I'm pretty relaxed which is why I'm somewhat wary of the 'newt' enemies in days gone, which are basically infected children.
TBH it's not the quality of the graphics I'd find off putting in a game, it's how they treat the violence. TLOU2 looks to be graphic but doesn't appear to revel in it, quite the opposite really. Whereas even now I find the bit in GOW3 where Kratos rips off Helios' head hard to watch as it lingers on the pain being inflicted and the tearing of flesh.
Aside from that, anything underwater where it's dark terrifies me to the point where the sub missions in GTA5 give me sweaty palms! Doesn't even have to be an enemy, could just be a big submarine hoving into view and I'd pap myself!