Bizarrely enough, this is actually a Knight Typal list
However, it took much longer for the progenitor of all dragons, the titanic Ur-Dragon, to actually appear on a Magic card
Number 169 Language English Legal Formats Brawl, Commander, Competitive Brawl, Legacy, Timeless, Vintage Not Legal Formats Alchemy, Pauper, Standard Banned Formats Historic, Modern, Pioneer Rulings (10/4/2019) The earliest opportunity you have to cast Once Upon a Time is during the first player's upkeep, before that player can play a land.
Or you can use it to copy dorks you made too, but do note that this will only copy what was made that turn, so it's often worse than populate since if your token you want to copy didn't enter that turn you'd be stuck
Having a precon at the ready gives you a lower power option when you need it, without having to worry about brewing something thats outside of your usual scope