Phantom Tales of the Night
Totsukuni no Shoujo
Trash of the Count's Family
Noblesse(haven't read yet)
Eleceed (tiiiiiiiiiniest little hints at possible future relationship in later chapters)
Mononobe Koshoten Kaikitan
The Dark Magician Transmigrates After 66666 Years
Lookism
Bless
Platinum End (haven't read yet)
I Became the Male Lead’s Adopted Daughter
Migi & Dali
Uratarou (can't remember if there was significant romance, but I remember the art was stunning and unique)
Jojo's Bizarre Adventure (art gets better as it progresses)
Youjo Senki (haven't read yet)
Non romance story with pretty art