I'd say 'Naruto' is a top choice. It has a rich world-building, diverse characters, and a conclusion that ties up most loose ends. Plus, it's had a huge influence on the manga industry.
There are many good love comics that you can refer to:
1. Your Name. (Your An animated film directed by Makoto Shinkai tells the story of two young people who discover the meaning of their existence to each other through the exchange of experiences in their dreams. It's very touching.
Attack on Titan: A very popular Japanese manga story about humans fighting giants to protect their walls. It is full of exciting battles and touching emotions.
3. Steins;Gate: This is a comic about time travel, about a group of scientists who use time travel experiments to discover some shocking facts.
" Your Lie in April " was a very touching romance manga about a young man who discovered that his teacher was a snail he had once saved, and a wonderful love story unfolded.
5 Death Note: This is a story about a genius high school student and a mystery full of thrills and suspense, while also exploring issues of morality and justice.