If you're looking for manga similar to Heaven's Door (Ranko HONGOU), you might like these titles. All recommendations are made by Anime-Planet users like you!
A devil-may-care playboy encounters a girl who will change him and his views on life forever.
If you like Renri no Eda or Heaven's Door you will probably like the other because both are short one volume tragic romances dealing with terminal illness and death. In both manga both main characters are dying but by chance fall in love and help eachother deal with whats to come.