I currently have 3 shinies, Not including the automatic red gyarados you get in HG/SS
A Shiny Gyarados I found as a magikarp in Mt.Coronet on my platinum version as I was searching for feebas.
I came across a shiny cressilia while I was Training one of my other pokemon, happened the same day as the Gyrados
A shiny Nidoqueen I found as a Nidoran F in the safari zone in HG. I'm currently using it in my battle frontier team.
I did have a shiny raticate I found in the gold version way back, but I think the save file was deleted at some point, same thing with a blue electrike.

A Shiny Gyarados I found as a magikarp in Mt.Coronet on my platinum version as I was searching for feebas.

I came across a shiny cressilia while I was Training one of my other pokemon, happened the same day as the Gyrados

A shiny Nidoqueen I found as a Nidoran F in the safari zone in HG. I'm currently using it in my battle frontier team.
I did have a shiny raticate I found in the gold version way back, but I think the save file was deleted at some point, same thing with a blue electrike.