Lucia is another excellent choice. Her story arc is intertwined with the main plot in interesting ways. She brings a unique perspective, being from a different background, and her skills, both in and out of combat, contribute to the progression of the story. Moreover, her interactions with other characters are well - written and add to the overall atmosphere of the game.
Kwon is a great companion for the story. He has a strong sense of loyalty and his backstory adds depth to the overall narrative. His combat skills also come in handy during various missions.
Ranger Wolf is a good option. He's a tough and no - nonsense type. His past experiences as a ranger give him a certain edge and his dialogue throughout the story often reveals interesting insights about the world of Wasteland 3. His combat proficiency helps in the more dangerous parts of the story.
Gale is another excellent choice. His pursuit of magic and the mystery surrounding his condition with the Netherese orb. His relationship with Mystra and his attempts to regain his former status contribute to the story in many ways. He also has a lot of knowledge about the lore, which enriches the story as you progress.
In the BG3 story, some of the best companions are Shadowheart. She has a mysterious past and her own beliefs that add depth to the story. Another great one is Gale. His knowledge of magic and his personal quest for power and redemption make him an interesting character to have around.
Aloth is a great choice. He has a complex backstory involving his secretive order, which adds depth to the overall story. Another good one is Eder. His loyalty and the mystery surrounding his family's past are interesting elements that tie into the game's story.
Lae'zel has a fascinating story too. Being a Githyanki warrior, her loyalty to her people, her beliefs about the creche and her experiences that make her question and grow throughout the game add depth to her story.
Pallegina can be a top pick as well. Her unique background as a paladin with ties to different factions brings in a new perspective to the story. Her moral code and how it clashes or aligns with the player's decisions throughout the game make for a great addition to the story experience.
Fane can be considered one of the best companions story - wise. His unique perspective as an undead and his backstory add a lot to the overall story experience. Also, Red Prince is quite good. His quest for power and his cultural background bring a lot of depth to the story.
Well, without more context, it's hard to be specific. But perhaps these are stories where the companions in Radiata have unique abilities that complement each other. For example, one might be a skilled archer, another a powerful mage, and they form an unbeatable team. They could go on quests to save the Radiata land from an evil sorcerer or some kind of natural disaster, and their bond is what makes their story great.
I'd say Shadowheart is a must - mention. Her backstory is full of mystery. She has been sent on a mission by Shar, but as she progresses, she starts to question her faith and her role. Astarion's vampire nature gives his story a dark and alluring aspect. His struggle for freedom from Cazador is a central part of his story arc. And Gale, his connection to the goddess Mystra and his attempts to control his magic while dealing with his past mistakes make his story really captivating.
Pallegina has a very unique story too. Her connection to the Vailian Republics and her sense of duty are central to her story. Her conflicts between her personal beliefs and the orders she has to follow add a lot of intrigue. Also, her cultural background gives a different flavor to her story compared to other companions.