Well, 'Beyond the Border Walls' is a really cool fanfic. It focuses on a group of characters who are trying to break through some hidden barriers in the Border world. It has some great action scenes and character development. Also, 'A Border's Secret Alliance' is quite good. It reveals some secret relationships between different factions in the Border manga's setting.
Berserk is also a great choice. It follows the story of Guts, a lone mercenary with a tragic past. The manga has a dark and gritty atmosphere, with detailed art and a complex story that delves into themes like fate, revenge, and the nature of power. It's not for the faint of heart but offers a truly immersive reading experience.
You should check out 'Attack on Titan'. It offers a unique and intense post-apocalyptic setting, complex characters, and a plot that keeps you on the edge of your seat.
You should try 'Ouran High School Host Club'. It's not just romantic but also full of comedy and charming characters. The plot is both fun and heartwarming.
You could try 'Fullmetal Alchemist'. It's a classic with a compelling plot, deep themes, and excellent world-building. The story is both exciting and thought-provoking, making it a great choice for those new to manga.