Sure. You can find them on various fanfiction websites. Look for ones that have high ratings and good reviews. Some might focus on crossovers where the characters from Death Note interact with those from My Hero Academia in unique scenarios. It could be a hero from My Hero Academia trying to stop someone misusing a Death Note - style power, or a Death Note character being influenced by the hero - centric society in My Hero Academia.
Ryuk would probably just be amused. He is a Shinigami who has seen a lot in his existence. Fanfiction is just another strange human creation to him. He might chuckle at some of the more outlandish ideas in the fanfictions, like a character having superpowers beyond the Death Note.
Misa would likely be excited. She is a big fan of Light and the whole 'Kira' concept. In fanfiction, if there are scenarios where she has more power or a closer relationship with Light, she would be all for it. However, she might also get jealous if there are other female characters getting too close to Light in the fanfictions.
Oh, for sure! Death Note is considered a masterpiece in the manga world. Its unique concept and the way it unfolds make it a must-read. The characters' development and the moral dilemmas presented make it stand out from the crowd.