Doraemon

Both contains a boy with glasses as a main character. Korosuke share similar traits of Doreamon, Miyoko share similar traits of Shizuka, Buta Gorilla share similar traits of Gyan. They both have similar art style and friend ship with each others. They both contains use of high class inventions and Time travel is mostly used. They both have comedy and main character helps others even after being bullied by his friends. Both series shares a number of interests.  

Both of the series' main characters are robots who have a liking for one certain type of food and live with boys with normal Japanese families. They always run into trouble. 

Both involve magical wise-cracking creatures who go on silly adventures and wacky hijinks with young boys.