Lottie Tuwinnit an NPC inside Springlade at 31, 59 KV sells Lottery Tickets for 10gp a piece, every week during Sunday Maintenance the lottery is drawn and one random person holding a ticket chosen as the Lottery Winner.
The lottery winner receives one of the following Boss cards, which to my knowledge can not be obtained anywhere else.
The more tickets you buy the greater the chance of you being chosen the winner, but remember that random number generator is an evil demon!
Check the announcements on Sunday to see if you were the winner, the winner will have the card automatically added to their card list regardless of if they are at or over their card limit.