Top major legends would be Lugia, Fug, Palkia/Giratina, Zekrom, Yveltal, and Necrozma.
I also like Mewtwo, Deoxys, Darkrai, and Genesect equally.
For pixies it's Mew, Victini, and Marshadow.
And for minor trios I like the Beasts, Regis, and Genies-Therian formes only.
Also like all of the Tapus for expanding the character of the Fairy type(they REALLY fit the old folklore with their fickle attitudes and incomprehensible motives).