When I started cataloging my Magic collection, I started with my Black section (the smallest), and quickly discovered that if I was to have a complete catalog, I had to list all the sets that my cards were from, as well as the number of each card I had, the condition it was in, etc
For the uninitiated, Dack Fayden was the lead protagonist of a series of Magic: The Gathering comics, where he was dubbed 'The Greatest Thief in the Multiverse.' Befitting of his card, then, to literally steal artifacts, and that's without mention of his equally useful +1 and rarely-achieved -6, which steals everything
All that really means is you have to make sure you dont have any duplicate copies of creatures in your deck, or at least you dont have very many
1 Oblivion Ring
While one mana is pretty easy to pay, the ward effect has the potential to keep your creature protected across several turns, or at least tax your opponent so they cant do multiple things in a turn