Babylonia (7th Singularity): Abandoned City Babylon (Free Quest) is the best AP-saving & time-saving location to farm Yggdrasil Seed. You'll get around 5x Yggdrasil Seed by spending 200 AP.
Orleans (1st Singularity): Jula (Free Quest) is the first location you unlock to farm Yggdrasil Seed.
Rashoumon event (Ibaraki Douji event)
Murder at the Kogetsukan
Inheritance of Glory
5 Star Servants Tier List: Best Servants [5/9 updated!]
Demon (Demonic) Servants & Enemies
Best Servants [★4]: 4 Star Tier List
Anne Bonny & Mary Read (Rider)