Ojutai, Soul of Winter [Dragon]: Was occasionally useful when it was in standard
Mechanics in the style of defender have been in the game since Alpha, when the Wall creature type was introduced
The closest I could find to anybody doing it in the mainstream recently was Artifact (I know, I know, I'm stretching the word "mainstream" here) with a slightly bastardised version of the concept handled via Steam's marketplace, and even then it's still an online auction house, not just doing fun swaps with your pals and saying "well I've got this, what've you got?", like exchanging the best parts of your packed lunches at school
They can also be defender creatures that, when a certain condition is met, can attack
Dip into Mark Rosewaters Vision Design article, and youll find Silverquills student archetypes are listed as ROTC, mean girls, jocks, privileged kids, overachievers
While they know they can sell some of the items, they've also opened a few of the boxes