There were many classic examples of animes that could transform or transmigrate:
1.<< Index of Forbidden Magic Books >>: The protagonist, Dangma Sujo, traveled to the future in an accident and became a teenager with superpowers.
Naruto: The protagonist, Naruto Uzumaki, obtained the power of the tail beast in an accident and became the most powerful figure in the Ninja Village.
3. Inuyasha: The protagonist, Inuyasha, is a warrior who travels through time and space to destroy many monsters with other characters.
4 " Death ": The protagonist, Orihime Inoue, is a transmigrator who has traveled to different worlds and engaged in fierce battles with various characters.
5 Naruto Stormy Legend: After Naruto became Naruto, his companions experienced a series of adventures, including crossing time and space to fight and solve various events.
There were many similar time-traveling anime such as Naruto, One Piece, Reaper, Gintama, Inuyasha, Detective Conan, Attack on the Giant, Full Time Master, Extinguisher, Sword God Realm, Date Battle, Forbidden Magic Book Catalog, Even a chuunibyou needs to fall in love! Magical Girl Little Yuan, Life in the Other World from Zero, Future Diary, About My Reincarnation as a Slime, My Hero Academy, Tokyo Ghoul, and so on.
Time-traveling anime novels usually referred to the story of the protagonist transmigrating into the anime world. This kind of plot was more common. In the world of anime novels, the protagonist may encounter various anime characters and interact with them. This kind of plot could allow the readers to enjoy the feeling similar to watching an anime while also bringing different experiences and challenges to the protagonist.
You can start from the chapter where the anime ended. Usually, there are online forums or manga communities that can give you the exact chapter number.