There's Eris Boreas Greyrat. She is an important character as she has a complex relationship with Rudeus. She is strong - willed and her growth as a character is interesting to follow. Another one is Sylphiette. She is a friend of Rudeus and has her own story arc related to magic and her identity. Then there's Paul Greyrat, Rudeus's father, who also plays a significant role in the story, especially in terms of family dynamics.
In the manga, Sasuke doesn't regain his Rinnegan. The story progresses without this particular change. The power he had before is maintained without reverting or regaining additional abilities related to the Rinnegan.
Thor's getting his eye back in the comics depends on the specific comic arc. Sometimes it happens as part of a major plot twist or a heroic achievement on his part.