Gale's story is quite interesting too. His relationship with Mystra and his struggle with the dangerous magic item he has within him add depth to his character. His journey to either redeem himself or find a new path in life while dealing with the consequences of his past actions is a great part of the BG3 companion stories.
Wyll is an interesting companion. He made a pact with a devil, Mizora, in order to gain power to be a hero. His story is all about his attempts to redeem himself and break free from the devil's hold. His relationship with the other companions and his decisions based on his moral code are key parts of his story. Karlach is another great companion. She has a heart of gold despite being a tiefling. She escaped from the hells but is haunted by her past there and her time with Zariel. Her story is one of survival and finding a place in the world.
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.
Character depth makes some BG3 companions have great stories. For example, Gale's internal conflict about his magic and past mistakes gives his story depth. Complex relationships also matter. Astarion's relationship with the other companions, especially as he tries to hide his true nature at first, adds to the richness of his story. Their goals and quests are important too. Lae'zel's goal to serve her people and how that clashes with the group's aims at times makes her story engaging.
For Gale, it's his connection to magic and his past mistake. He's a wizard who has made a huge error with a powerful magic item, and his story is all about redemption and dealing with the consequences of his actions. This makes his story really interesting.
For a magic - focused playthrough, Gale is an excellent companion. His vast knowledge of magic can be really helpful. He can offer insights on different spells and magical artifacts. Shadowheart also has some useful magic - related abilities, especially with her cleric powers.
Lae'zel has a very memorable story. She's a Githyanki warrior with a strong sense of purpose. Her loyalty to Vlaakith and then her journey of self - discovery as she begins to question her own beliefs and the Githyanki way of life. It's a story of breaking free from dogma and finding one's own truth in a very harsh and unforgiving world.
For me, Halsin has a wonderful story. His connection to nature and his role as a druid are central to his story. He has to deal with threats to the natural world and also his own personal growth, especially when it comes to his relationships with others outside of his druidic circle. His story is a gentle exploration of nature, community, and self - discovery.
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.
It depends on personal preferences. Some might say Lohse has the best story quests as they offer depth and variety.
The Githyanki have great stories. Their history of war and their complex relationship with Vlaakith is full of intrigue. They are a race with a strong warrior culture and a lot of internal politics.