For 'fate crossover fanfiction', you could consider a crossover with 'One Piece'. The Servants might be pirates or marines, sailing the Grand Line. A 'Fate' and 'Fullmetal Alchemist' crossover would also be cool. Picture Servants trying to solve the mysteries of alchemy. There's also potential in a 'Fate' and 'My Hero Academia' crossover, with Servants having Quirks.
Well, a great 'fate crossover fanfiction' idea is a crossover with 'Dragon Ball'. Imagine the Servants having to face off against Saiyans or other powerful foes from the Dragon Ball universe. You could also do a 'Fate' and 'Final Fantasy' crossover. The different classes and magic systems in both could create really interesting storylines. And a 'Fate' and 'Pokemon' crossover where Servants befriend and battle with Pokemon.
Well, in scp fate crossover fanfiction, there could be crossovers where the containment procedures of SCPs are challenged by the chaotic nature of the Fate universe. Some fics might explore the idea of SCPs being summoned as Servants, which would bring a whole new level of danger and unpredictability to the story. It could also involve the SCP Foundation trying to either use or stop the Holy Grail War depending on how they perceive it as a threat or an opportunity.
A cool Fate Extra Crossover Fanfiction idea is to cross it with the world of Attack on Titan. The servants could help in the fight against the Titans. Like Berserker could use his brute strength to take on the huge Titans. Also, a crossover with the Naruto universe would be exciting. Servants might learn ninja techniques or have battles against the powerful ninjas there.
One idea could be to have the characters from RWBY enter the Fate universe and participate in a Holy Grail War. Ruby could be a Saber - class servant with her scythe as her weapon. Another idea is to have the Fate characters visit Remnant and help the RWBY team fight the Grimm. For example, Archer could use his projection magic to create weapons for the RWBY team.
One idea could be a crossover between Fate/Stay Night and another popular anime like Naruto. You could have the Servants from Fate interacting with the ninja world. For example, Saber could face off against Naruto in a battle of ideals. Another idea is a crossover with Harry Potter. Imagine the mages in the Fate universe collaborating with Hogwarts students to fight a common magical threat. Or a crossover with Attack on Titan, where the Servants help the Survey Corps in their fight against the Titans.
One idea could be a crossover with the Justice League. Dr Fate could use his magic to help the League against a powerful magical threat that they can't handle alone. Maybe a dark sorcerer from another dimension is trying to invade Earth, and Dr Fate's knowledge of ancient magic is crucial in devising a counter - attack.
Perhaps in an 'scp fate go crossover fanfiction', the concept of Command Spells could be linked to SCP artifacts. Imagine a Master finding an SCP that gives them an enhanced form of Command Spells, but with a dangerous side - effect. Or a Servant could be bound to an SCP - like entity instead of a traditional Master - Servant contract. For instance, a Servant of the Berserker class could be paired with an SCP that enhances their rage and power but also slowly drives them madder than they already are in their Berserker state.
One idea could be that the Servants from Fate are transported to the Halo universe. For example, Saber could find herself in a battle against the Covenant. Her noble phantasm could be a powerful weapon against the alien foes. Another plot could involve Master - Spartan team - pairings. A Spartan could be paired with a mage to fight a common enemy that threatens both the Halo and Fate worlds.
A crossover with the Naruto universe could also be exciting. Imagine Servants like Archer using their skills against ninjas. Naruto characters might be intrigued by the concept of Servants and their powers. It could lead to a story where they exchange combat techniques and learn from each other.
A cool 'fate stay night crossover fanfiction' idea might be a crossover with 'Final Fantasy'. The different classes and magic systems in Final Fantasy could blend well with the Fate universe. For example, a character from Fate could learn the job classes from Final Fantasy. Also, a crossover with 'Persona' could be interesting. The Velvet Room and the concept of personas could be integrated into the Fate world, adding a new layer of mystery and power to the story.
One idea could be that Naruto is summoned into the Fate universe during the Holy Grail War. He might be mistaken for a Servant at first. His unique ninja abilities would disrupt the normal flow of the war. For example, his Shadow Clone Jutsu could be used to confuse the enemy Masters and Servants.