One popular ability manhwa fanfiction is 'The Awakened One's Journey'. It focuses on a character who discovers a unique ability and has to navigate a dangerous world. Another great one could be 'Ability Wars' which has intense battles between characters with different powers. And 'Mystic Abilities' is also interesting as it delves into the origin of these special abilities in the manhwa world.
In many cases, it is legal to read manhwa online if it's from authorized and legitimate platforms. But reading from unauthorized or pirated sources is illegal.
Another must-read manhwa in 2020 was 'The God of High School'. It combined exciting battles with a compelling narrative. The diverse characters and their growth throughout the story made it a standout.