Spell or Style Trainer
The Spell / Style Trainer screen can be used to find spell or style trainers in the current realm, it will only show those that are accessible so if a trainer is in a building and the building is not explored then it will not show up on this screen.

If you click on the lsited trainer you will be teleported to the same location as them but not the same building, you will still need to enter the building to find the trainer.