Some comics I recommend:

Gunnerkrigg CourtWitchyNimona (v, c)SuperCakes
Monster Pulse ♦ Lady of the Shard (c, n) ♦ Questionable Content (n, t)
♦ Ava’s Demon (v) ♦ The Property of Hate ♦ Brainchild ♦ Slightly Damned (v) ♦
ShootAround (c, v)NamesakeThe Order of the Stick
♦ Hark, A Vagrant ♦ Striped Socks (h) ♦ xkcd ♦ Prague Race (v) ♦ Hinges ♦
Stand Still, Stay Silent (v)Always Human ♦ Manic Pixie Nightmare Girls (t)
Assigned MaleStrangely Katie’s comics (c) ♦ FindChaos (v, n)
Emily Carroll’s comics (v, c) ♦ Death and the Maiden part 1 (c), part 2 (h)
Blindsprings ♦ Dinosaur Comics ♦ A Softer World (c) ♦ All Night
ChaosLifeEvery Day (c) ♦ The Meek (n)Mare Internum (t) ♦ Forever (c)
♦ Lackadaisy (v) ♦ Necropolis ♦ Humon Comics (n)Hotblood!
Three Word Phrase (n)Love Me NiceTripping Over You
WondermarkTwo Guys and GuyBroken Telephone (v)The Awakened (n) ♦

Note:
h = on hiatus
c = complete, or multiple standalone short stories
v = contains some violence or gore or body horror
n = contains some nudity and/or sexual content shown
t = other particularly troubling themes? vague, I know, but may include suicide, sexual abuse, etc.
If you want to know specifics or think I missed something, feel free to message me

(as far as I can remember, as of putting this list together)