Since I'm no good at introductions, I'll just give mine.
I really like Wooper's because it makes it look like a real axolotl. Sure, the 3D games kinda drained some color from it, but I like the kind of pink shiny Wooper has.
Now, I know a lot of people are gonna hate me for this, but I really like shinies that use lime/neon green, like Ursaring, Stantler, and...

...yeah. I really like shiny Espeon. I will agree that the 3D games uglified it, but from Generations III to V it had a lime color I'm sad isn't used on a lot of Pokémon that aren't shiny.
I also think Ralts's is pretty good. Nothing too extraordinary about it, but I do like the blue "hair" and the lavender body a lot.
Speaking of colors that aren't on Pokémon very often, green and purple is a combo I don't see much either, which is why I'm glad we have the Budew family. Sure, the Deino family has that too, but their green is too dark for my tastes.


I really like Boldore's and Gigalith's, too, because the bright blue ores really sell the idea that shiny Boldore and Gigalith are more valuable.

Have you seen Clauncher's and Clawitzer's? Those are also pretty good.

Also speaking of green, I really like shiny Rowlet. Aquamarine is also another favorite of mine, and I like that most of Rowlet's body is aquamarine.
I also really like how the Galar birds' shinies are references to their Kantonian counterparts. If only they weren't shiny-locked...


I also like the shinies of the Galarian Zigzagoon family. You can rarely go wrong with Porygon's color scheme.


Also, here's a link to what all shiny Pokémon look like, if you're not familiar with many of them.