In fact, I can think of at least two other cards for which exactly one copy exists
I can't promise that you'll win all your games, but I will promise that you'll have a ton of fun along the way
Illustrated by Rudy Siswanto Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Legal Comp
Rhystic Study often gets a draw off of every spell an opponent casts even when they know the unwritten rule when facing a Rhystic Study- "ALWAYS PAY FOR RHYSTIC STUDY." And make no mistake, always pay
Blasting Station Blasting Station is often featured as a key component in infinite combos, especially those in non-black or red color combinations like the many variations of Karmic Guide or Darien, King of Kjeldor combos

The shafts I used were made for these O-rings (on amazon.ca): uxcell Silicone O-Ring, 18mm OD, 12mm ID, 3mm Width, VMQ Seal Rings Gasket, White, Pack of 10 MTG_Shuffler_Shaft_v2 are the re-designed shafts with grooves to hold o-rings (the amazon link above) - if you print these, then don't print the shafts in the card.shuffler.v3mrb-parts.3mf file (right click on them and uncheck printable) nor the card.shuffler.shaft.rubber-band.3mf file if you're using small rubber bands, print the card.shuffler.shaft.rubber-band.3mf file (resized from the previous model) lastly, the shafts in the card.shuffler.v3mrb-parts.3mf don't have a groove, and could be plasti-dipped or used with U-shaped seals that wrap around the disc I was more comfortable in Fusion360, so I used it for the redesigned shaft (o-ring variant)