The relationships. Seeing other characters be protective of Ash shows a deep bond. For example, Pikachu being protective adds an emotional touch as it's his closest companion.
Sure. You can check out some popular fanfiction websites like Archive of Our Own. Just search for 'Protective Ash' there and you'll find a variety of stories.
Well, perhaps in the fanfiction, Mewtwo decides to protect Ash. Mewtwo, being so powerful, could create barriers around Ash whenever he's in danger, like when facing a horde of wild and aggressive Pokemon. It might also use its telepathy to communicate with Ash and guide him to safety.
A good one often has well - developed characters. For example, Sabrina's protective nature should be shown in a believable way, like how she defends Ash from other powerful Pokemon trainers or dangerous situations. Also, the relationship between Ash and Sabrina should grow organically. It shouldn't feel forced.
You can try looking on fanfiction websites like FanFiction.net or Archive of Our Own. They usually have a large collection of Pokemon fanfictions, and you might be able to find the Ash x Protective Sabrina ones there.
Probably Poseidon, as he is Percy's father and has a vested interest in his son's well - being. Zeus might also be protective in some cases, despite their past differences, as Percy is a hero who often saves the world which benefits Zeus's realm as well.
In some versions, Neville could also be one of Harry's protective mates. Neville, who grows in courage throughout the series, would be willing to stand up against any threat to Harry. And Luna, with her unique perspective and magical abilities, might also be part of Harry's protective group.
Their shared experiences play a big role. They've been through so much together, like countless battles and adventures. Percy has seen Annabeth in tough situations and he knows how strong she is, but also how vulnerable. So he feels the need to protect her. For instance, they might have had a close call in a previous adventure where Annabeth was nearly killed, and that memory makes Percy extra vigilant.
Perhaps Anko has a personal connection to Naruto. Maybe she sees a bit of herself in him, like his determination in the face of difficulties, and this makes her feel a sense of kinship and thus the need to protect him.