Time travel novels usually referred to novels in which the protagonist traveled to a different era or world, often accompanied by various fantasy, adventure, and love elements. The following are some common types of time-travel novels and their characteristics: 1. Fantasy travel: The protagonist travels to the fantasy world to improve his strength through cultivation and combat. It is usually accompanied by elements such as magic, mythical beasts, and myths and legends. 2. Romance travel: The protagonist travels to an ancient romance story and becomes the heroine. He experiences all kinds of love and emotional entanglements, usually accompanied by elements such as the palace, Jianghu, and family. 3. Sci-fi time-travel: The protagonist time-travels to the future or an alien world to explore and change the world through technology and scientific means. It is usually accompanied by elements such as technology, alien creatures, and the universe. 4. Historical travel: The protagonist travels to a certain historical story to change the course of history. Playing different roles is usually accompanied by elements such as history, politics, and war. The plot of a time-travel novel was complicated, and it often involved various relationships and conflicts of interest. At the same time, it also required the protagonist to have enough wisdom and ability to deal with various challenges. Time travel novels were also one of the most popular online literature genre.