2 fairly recent American cartoons that I would like to recommend to horror/splatter lovers.

Ugly Americans (2010–2012) created by Devin Clark.

Set in a city populated by humans and monsters of all kinds, we follow the story of Mark Lilly, a social worker who works for the Department of Integration.

Integration of monsters of all kinds, werewolves, demonic children, blobs, zombies, demons, vampires and many others.

In the middle is David M. Stern who had written several episodes for The Simpsons in the 90s.

Two seasons, the first of 14 episodes and the second of 17 episodes.

About 20 minutes for episode.

Season 1 episode list:

1 “Pilot” “D.O.I. Cutbacks”
2 “An American Werewolf in America”
3 "Demon Baby"
4 “Blob Gets Job”
5 “Treegasm”
6 “So, You Want to Be a Vampire?”
7 “Kong of Queens”
8 “Better Off Undead”
9 “Kill… Mark, Kill”
10 "Sympathy for the Devil"
11 "Hell for the Holidays"
12 “Trolling for Terror”
13 "Soul Sucker"
14 "The Manbirds"

Season 2 episode list:

1 Wet Hot Demonic Summer
2 Callie and Her Sister
3 Ride Me to Hell
4 G. I. Twayne
5 The Ring of Powers
6 The Clone Wars
7 Wail Street
8 Little Ship of Horrors
9 Lilly and the Beast
10 Mummy Dearest
11 Journey to the Center of Twayne
12 Any Given Workday
13 The Roast of Twayne Boneraper
14 Mark Loves Dick
15 The Stalking Dead
16 The Dork Knight
17 Fools for Love

Mr. Pickles (2013–2018) created by Will Carsola and Dave Stewart.

In the town of Old Town, the Goodman family has a dog called Mr. Pickles who enjoys killing people.

The only one who seems to notice all this is the grandfather of the family.

Three seasons in total for now.

About 10 minutes for episode.

Season 1 episode list:

1 Tommy's Big Job
2 Father's Day Pie
3 Foul Ball
4 The Cheeseman
5 Dead Man's Curve
6 Loose Tooth
7 Grandpa's Night Out
8 Coma
9 Where is Mr. Pickles?
10 The Lair

Season 2 episode list:

1 Mental Asylum
2 Cops and Robbers
3 Serial Killers
4 Shövenpucker
5 Fish?
6 A.D.D (Detective Astronaut Dolphin)
7 My Dear Boy
8 Vegans
9 Talent Show
10 Season 2 Finale

Season 3 episode list:

1 Brain Download
2 Momma's Boy
3 S.H.O.E.S.
4 Telemarketers Are the Devil
5 Gorzoth
6 Tommy Goes to School
7 Sheriffs
8 Bullies
9 Tommy's Cartoon
10 Season 3 Finale

Both series are very entertaining, well written, and teeming with horror movie quotes.