Winter Orb or Millstone, and Ive even seen two sacrificed for and early Icy Manipulator
Many ideas and mechanics that used to be silver-border are now printed in black-bordered sets, sometimes 1-for-1 When people approach me about silver-bordered cards in Commander, the most common topics are (in no particular order) Host/Augment (and Surgeon General Commander), Acornelia, Krarks Other Thumb (and other coin flipping/dice rolling cards from Unglued), and Contraptions
Or my Pia Nalaar, Consul of Revival deck
The next closest two, Andrew Smith and Federico Bastos, have notched "just" 23,000 and 22,000 respectively
Cards that immediately spring to mind for abuse with Prodigy are Snapcaster Mage and Burning-Tree Emissary, a wizard and shaman, respectively
On the one hand, they die to board wipes, and on the other hand, they also synergize with creature-based strategies