Perhaps the fanfic could explore how Harry's past experiences with Voldemort shape his parenting. He might be overprotective at times due to all the danger he has faced. His children could also inherit some of his unique magical abilities, and he has to guide them in controlling and using those powers properly. The story could also involve his friends, like Hermione and Ron, helping him out with the kids, and the kids forming strong bonds with their 'aunt' and 'uncle'.
New dark wizards or witches could emerge. They might target Harry's children, seeing them as a potential threat in the future due to their connection to Harry Potter. They could try to kidnap the children to use them as leverage against Harry or to turn them to the dark side.
Maybe the story could revolve around Harry dealing with the loss of his wife, who was a muggle actress. He might struggle with raising their children alone while also trying to keep the wizarding world a secret from them, just like he had to keep secrets from his muggle relatives.
One possible storyline could be that Harry discovers a magical plant that has the power to heal serious wounds. He then devotes his time to protecting this plant from dark wizards who want to use it for evil. This could lead to a series of adventures where he has to hide the plant in different magical locations and fend off attackers.
One possible storyline could be that the child is a result of a relationship Harry had during his later years at Hogwarts that was kept secret. Maybe it was with a foreign witch he met during one of his adventures outside of Hogwarts. The child could inherit Harry's magical abilities and also some of his personality traits like his courage and sense of justice. Then the story could focus on how the child discovers his or her true identity and the legacy of being Harry Potter's offspring.
One could be that Charlie takes Harry on a dragon - watching adventure. Harry gets to learn more about dragons, which he has always been interested in. Charlie shares his knowledge and experiences, and they form a closer bond as friends.
One possible new storyline could be that there's a magical competition that involves not just the Hogwarts houses but also other magical institutions around the world. The competition could have a Disney - style grand prize, like a magical artifact that has the power to grant wishes. Along the way, the characters would face various challenges and make new friends and enemies from different magical backgrounds. This would expand the scope of the Harry Potter world and bring in new elements of magic and adventure.
Well, maybe Harry has to deal with the expectations and powers that come from being Sasjhowmaru's son. There could be battles against dark forces tied to his parentage and quests to understand his true identity.
One possible storyline could be Sky Harry discovers a hidden magic within Hogwarts that no one else knew about. Maybe it's a secret chamber that holds the key to an ancient magic that can defeat the darkest of dark wizards. Another could be Sky Harry having the ability to communicate with magical creatures in a unique way, leading to him forming an alliance with them to protect the wizarding world. And he might also have a special connection to the stars (sky), which gives him extra powers during certain celestial events.
Obviously, the muggle actress, his late wife. Her friends from the acting world could also be important characters. They might come to check on Harry and the kids, if they had any, and share stories about her time in the acting business.
A possible storyline is that the wizarding world is trying to integrate more with the Muggle world after 19 years. There could be a plot where Harry and his friends are at the forefront of this movement. They might face opposition from some traditional wizarding families who are afraid of losing their pure - blood status or magical traditions. This could lead to all sorts of adventures and challenges for the characters as they try to bridge the gap between the two worlds.