For me, 'Tomie' stands out as extremely scary. The idea of an immortal and malevolent woman causing chaos and horror is terrifying. The detailed illustrations add to the creepy atmosphere.
Well, 'Tomie' is often considered a top choice. The way the character is portrayed and the mysterious plotlines make it stand out. Also, the art style adds to the overall creepy atmosphere.
Ito Junji was a very popular Japanese manga. His works were based on horror, suspense, and thrills. It was difficult to answer the question of which manga was the best because everyone's tastes were different, and everyone's preferences were different. Different people may like different works, so the best works may vary from person to person.
However, Ito Junji's works were usually of high production quality. The plot was compact and the visual effects were excellent. If you're looking for a good horror comic, I recommend you try Black Enchantress Academy, Devil's Kiss, and Death Note. These works all had unique styles and storylines that were worth reading.
You should avoid looking for free places to read Junji Ito manga. It's not legal and can harm the manga industry. Instead, try checking out your local library or subscribing to authorized digital platforms.