A long time ago there was a vague idea of saving the world from the apocalypse and the four horsemen of it and Servants cropping out of nowhere from a system devised from the Fuyuki grail and is this sounding somewhat familiar
A Nasuverse take on the Arthurian story Lanval
A story in which an old lady is taking care of a mansion with orphaned children all the same age except one that's slightly younger, and as the story goes you realize they're all reincarnations of SHIKI, Kohaku, Akiha, and Shiki; and so you can guess who the old lady taking care of them is, and yeah, I'm a jackass like that, I just want your pain and suffering.
A story which seems like its just a Shiki in school, only he's spouting some oddly chatty and philosophical things for Shiki, and then you realize its just before he's due to move back in with the Tohno, and then weird things start happening around town that he gets drawn into, and then in the end he confronts the fact that who he's about to down is actually Shiki Nanaya-taken-by-Roa, and he's actually SHIKI Tohno, and all he can do is lament how his family screwed over his best friend and would-be-brother's future.
Kiritsugu meets Maiya for the first time, then years later, Shirou meets Sigma.
Action bit of Bazett's actual meetings with Kotomine, and her eventual summoning of Lancer.
Shiki in Apocrypha. Shiki's limited life to the fullest vs Darnic's extended life for one reason. Shiki's inevitable doom of everything vs Amakusa's salvation. Shiki's gland vs a holy woman, an octopus woman, a man woman, and an elf woman.
On his Grand Justice Tour as an adult, Shirou comes across a prostitute about to be murdered by a mage for a ritual and befriends her, returning every so often to visit her as years go by.
I mean, I may get to these eventually, but once upon a time that was a lot more likely when I had time. Now I really don't.