2! Shiny Geodude from FireRed and Shiny Goldeen from Pokémon Black. Using Horde Encounter+Shiny Charm I have gotten a Shiny Cutiefly and Shiny Alolan Meowth. >w<'
My first full odds was a Foongus in Y, completely untintentional. Some other random shiny Pokémon I found were an Ariados and Fletchling in Sun. (I don't think I had the shiny charm when I found these 2? Not completely sure) EDIT: I also found a full odds Nidoran F and Burmy in PoGo one time.
The only one off the top of my head is a shiny Rattata I found in Castelia Sewers on White 2 version. I transferred it to Pokémon Home and never evolved it. Unfortunately it's one of those shinies that looks worse in 3D. The color went from a beautiful golden to a gross greenish yellow.