Huh, I've never thought about doing this, even though in retrospect it seems really obvious. Maybe it'll help me figure out my number one favorite Pokemon! Lol.
Normal: Ursaring - can't tell you why, I just really like it's design (and the fact that its shiny is bright green for some reason)
Fighting: Lucario - a bit cliche, but I do love its backstory with sensing aura, and its movie was one of my favorites
Flying: Noivern - apparently I like a lot of flying-types, but Noivern just has a super cool theme with the speaker-like ears
Poison: Scolipede - perhaps one of my favorite bug-types, especially because it's giant and can roll like a wheel
Ground: Flygon - because of course it is; but seriously, I love the goggle-like eyes and its sleekness compared to other dragons
Rock: Tyranitar - also a surprisingly tough choice, but I just think it has a really cool, unique, and intimidating design
Bug: Heracross - I've always liked Heracross because of its weird type-combo, and its mega evolution only makes it even cooler!
Ghost: Aegislash - because it's so unique and has one of the coolest shiny forms of all time (which I own!)
Steel: Metagross - it's so dang cool, has an awesome mega, and has a silver and gold shiny; what's not to like?
Fire: Quilava - as much as I love its whole evolutionary line, Quilava strikes the perfect balance between cute and cool
Water: Milotic - let's be real, I have like 5 favorite water-types, but I had to pick and I think Milotic is gorgeous
Grass: Sceptile - never before has there been a grass starter so unique and cool (except maybe Decidueye)
Electric: Luxray - felt like I had to pick this given that Shinx was the first shiny I ever found and caught!
Psychic: Gardevoir - also too many favorites; that said, shiny Mega Gardevoir would like to prepare your funeral now, thank you
Ice: Beartic - because apparently I like bears, especially bears with ice-beards
Dragon: Garchomp - I couldn't pick "all of them," and I feel like of all the pseudo-legendary dragons Garchomp is a cut above the rest in terms of coolness
Dark: Zoroark - loved the movie, love the unique ability, and love the side stories it gets in the Gen 5 games; all around awesome
Fairy: Togekiss - the second I heard fairy-type was a thing I knew this would be one, and I feel like it does a great job of representing its type's potential
Phew, that was harder than I thought it would be. But also fun! Welcome to LV by the way!