Staple Skills are skills that your character has right from the start. What goes under here is your species abilities they're born with and your classes abilities that they should have. For example, characters who are part fire spirit, are able to instantly create fire around their body, similar to Homura. Characters who are part of the bird tribe like Setsuna, get the free ability to fly. You write all this information in the skills & disciplines section of your character profile.
Ninjas staple skill would be using shundo, while Magical Duelists have the ability to do silent incantations and delay incantations. Wizards however have the ability to have more ferocious attacks and charging their spells.
Some ideas for staple skills would be:
Magical Duelist
Free Fighting Style: Magical Duelists are proficient at using a certain fighting style and excelling in using that fighting style, being able to learn and adapt to using numerous, important skills.
Faster, Weaker: Magical Duelists are very efficient in using quick spells for close combat fighting, however they're spells are often weaker.
Wizard