I've seen the recent posts about the impossible Treecko and Torchic VC shinies that seem to be mostly unobtainable now but did you know there was a time when you could get a 1:8 female ratio shiny Pokémon with the Gen 1 VC titles? These shinies are already completely lost to time.
Usually, these should be impossible because of how Gen 1/2 determines shininess. However, when Poké Transporter released for the Gen 1 VC, there was not only a bug on what determined shiny Pokémon, but the gender was also re-assigned with the correct gender ratio of that species when transferring it to Bank.
That means between 24 Jan 2017 and 5 Sep 2017 theoretically, you were be able to get the starters, fossils, eevee, and snorlax shiny if you hit the odds of 1:8,192 in game and then again 1:8 when transfering it. That's a combined total of 1:65,536!
Over the last two weeks I was busy developing a patch for Pokémon Bank to not only preserve the connectivity of Gen 6/7 games, but also to bring back this obscure fact in form of an Easter egg: https://github.com/devEnju/offline_bank
I'd love to hear on how you'd think to be able to hunt these Pokémon with the patch and hope you'll find the preservation as useful as I do.