Aside from Community Day Shinies, I have honestly had random spurts of luck getting full odds Shiny Pokemon in Go. The last one I got was Growlithe which I quickly evolved into Arcanine because it is one of my favorite pokemon from Gen 1. That was back on September 28th.
I also caught shiny Voltorb and Krikatot almost back to back in less than a week apart.
“I have found Holmes’ methodology of deductive reasoning to be quite
useful. One of his adages is that once you have eliminated the impossible,
whatever remains, however improbable, must be the truth.” - Lt. Cmdr. Data Moderator of:VPP & Pokemon Mobile