Yes, Mike Mignola does do Hellboy - and BPRD and Baltimore and Witchfinder and whatever other pies he manages to stick his fingers into. It's all amazing, though I'm a bit too squeamish for BPRD - it's too much body horror for me.
Hellboy is my personal favourite of his works, though Witchfinder is amazing too.
(from my favourite Hellboy story, The Island)
As for the other artists... I wouldn't call them macabre! XD
I mean, Nick Kole is 100% the nicest guy on the internet, and while he CAN draw scary stuff, he's mostly pastel candy colours and adorable things like this otter-person.
Murata Yusuke is currently drawing One Punch Man, but I fell in love with his style back when I found Eyeshield 21 (a manga about American football that is so good it will make you love American football, even though you're a noodle-armed dork who was permanently excused from gym class as a kid). Super-dynamic, amazing skill at character design, and hot dang, does he ever know how to layout a page. D:
Linda Medley is the creator of Castle Waiting, which is kind of a feminist take on fairytales, and is consistently both adorable and awesome. That bottom example is Sister Peace, the bearded nun, sharing cookies and a philosophy discussion with a tiny demon creature.
Aki Irie draws the gorgeous manga Ran to Haiiro no Sekai, which yes, does have an unsettling scene or two involving insects, but is mostly just so pretty it sparkles.
Iwaoka Hisae is the creator of Aomanju no mori (I think that's the japanese title? I'm amateur-translating from the Swedish title), which is a kind of magical realism slice-of-life story about a young man who lives in a little forest together with a bunch of domestic spirits.
Enrique Fernandez has drawn a bunch of comics, but the first one I read by him was L'ile sans sourir, a story about a lost sailor who gets stranded on an island where no one except one small girl still remembers what it's like to be happy.
Moebius is, well, Moebius. The one, the only, the legend.
Kawase Hasui mostly painted landscapes, and developed this really lovely, almost ligne claire style that really appeals to me: