>>36933984My first shiny Pokemon was either the shiny Haxorus or the shiny Gible in Black 2.
First caught shiny was a Horsea in Y, chainfished. Now a Kingdra.
First completely random shiny (no SOS, no radar, no dexnav, no egg hatching, etc.) was a Pinsir that appeared in Pelago, and has a catchdate of my birthday.
This Pinsir in particular is my favorite of all my shinies despite being modest and not having the right moveset, and is always on my team. It's named after Click the Scarabax Beetle, from Bionicle.