What modern knowledge or items could be used in a fantasy novel that traveled back in time?

" Strange Time Travel " is an ancient romance novel written by the author Ah Suo. The general plot of this novel is: The most unlucky transmigrator in history! Let's see how she can develop some modern gadgets in ancient times! A nonsensical idea, a funny plot, and an ancient life that made everyone laugh. ---------------------------- The Ancient Women's Survival Guide was an ancient romance novel written by Happy in a hurry. The general plot of the novel was as follows: What if he didn't know anything after transmigrating to ancient times? It doesn't matter. Someone will teach you. What should he do if he encountered a patient with severe cold and tsundere symptoms? It didn't matter, just torture him! What if all kinds of people came to find trouble with you? It's okay, give it back! ---------------------------- " Rejuvenated Time Travel " was a novel written by the author, Yue Sheng Cang Hai. The general plot of this novel was: Heaven will give this person a great responsibility, must first suffer his mind, splash his dog blood. Transmigration? Come on, it went out of fashion 800 years ago. Wuxia? What a joke, this kind of background was too old-fashioned. Young Master Xia, Young Master Xie, Fairy, Demoness? Noble sects, evil sects, treasures, the world? Wait a minute, what's up with the transmigration god? I've never heard of a retro style transmigration? ---------------------------- I Have the Female Lead's Halo After Transmigrating was an ancient romance novel written by the author, the idiot detective. The general plot of this novel was: She had accidentally transmigrated to a dynasty whose history could not be read, and she had even become an extremely ugly young lady of the Prime Minister's residence. Her first reaction was,"Can you please show me some favor, transmigrator?" This Host was too pitiful. Forget it, since she was already here, she would torture the scumbags when she was free and fall in love with them… ---------------------------- " Traversing Ancient Times, The Black-bellied General Loves Farming " was an ancient romance novel written by the author, The World Is All About You. The general plot of this novel was as follows: The modern middle-aged woman had transmigrated in her sleep and was dressed as a teenage girl. Oh my god, he was dozens of years younger and even had a free space. Wakaka… Just watch me farm, earn money, and flirt in ancient times… ---------------------------- " Love Through a Thousand Years " was an ancient romance novel written by the author, Feng Zhuang. The general plot of this novel was: As he walked, he transmigrated. Of course, this was nothing strange. Anyway, all kinds of transmigration methods had been used by people. But who is as unlucky as me to be caught? Sigh, actually, there's no need to make a fuss about this. I'm not the only female lead who was arrested. What if he was kidnapped? Was it considered unlucky? Haha, this is also nothing! Anyway, no matter how unlucky she was, there would still be handsome men, right? Since that was the case, he would continue to be unlucky! The plot is fictional, please do not imitate it. ---------------------------- " Crossing with a novel " was an ancient romance novel written by the author, Hong Se. The general plot of this novel was: He woke up and transmigrated? Had she transmigrated to the novel she was reading and become the female lead? ---------------------------- Being an Emperor in Ancient Times was a historical fiction novel written by the author, Xiao Jiong. The general plot of the novel was: Another transmigration? However, this time, he had to pacify the people, eradicate the evil, clean up the side of the king, and finally wear the yellow robe, rest the army, raise the people, and recover the lost land. Do you want to experience it? ---------------------------- " Online Writers 'Ancient Survival Records " was a historical fiction novel written by author Linghu Beyond. The general plot of this novel was: He was a part-time web novel writer, and he was also a writer who was used to failing all year round. He had thought that such a life would be normal until he transmigrated to ancient times… To put it simply, this was a story of an ordinary person who traveled to ancient times and made a fortune by writing novels. * During the new year, he suddenly had an idea. He wanted to write a novel about how ordinary web novelists survived in ancient times. The background of this book is fictional history. The author is not a history major. Although he has tried his best to check the information when writing, there are probably still bugs. Please forgive him... ---------------------------- " The World of Peerless Beauty for You " was an ancient romance novel written by the author, Yu Junjue. The general plot of this novel was: She had transmigrated to an era where she did not exist, but fortunately, she became the daughter of the Yu family. At least I don't have to worry about food or clothes. I wanted to live a comfortable life…But, people have their ups and downs, and the weather is unpredictable. The Yu family is being hunted down by enemies…It's so sad. How can a modern person like me defeat you masters…However, I'm not a vegetarian either…Watch how I play with the ancient times…The plot is fictional, please don't imitate it.