My first shiny was a shiny vulpix. I don't remember where I got it or even what game, it was such a long time ago, but it popped up on the screen and I just freaked out. I never knew you could get a shiny Pokemon until that moment. It was so pretty and sparkly. I already loved the adorable regular vulpix design and it's beautiful ninetales evolution so it was just so surprising and exciting to find that a different color was available. I also remember screaming so loud that my mom thought someone was in the house about to rob us or something. I did it a second time when it evolved into ninetales and it turned out to be silver which is my favorite color lol
My favorite shiny is ralts though. I always thought it was unfair that Wally got a ralts as his starter and when I first started ORAS he freakin encountered a shiny ralts... I started the game over just so he could have a regular one...
Either eevee or sylveon is the best for me, I can't decide. On one hand I like fluffy animals, but on the other, I like flowy design so I'm torn.
I breed thousands of eggs until I find a shiny with good stats and throw away the others breedjects.
My favorite shiny is Lopunny.
My fave eeveelution is Sylveon because Pixilate + Pixie Plate + Hyper Voice + Random Irrelevant EVs = Death