Gitaxian Probe + Mishra's Bauble Let's put it this way: A cantrip that you can pay for with life rather than mana, and tells you what your foe's up to, is so fundamentally broken that Gitaxian Probe is banned in Modern and Legacy, and it's also restricted in Vintage, where it's no stranger to top-tier decks
Love this subtle little thang all up and down the block
When you exile a nonland card this way, Hidetsugu, Devouring Chaos deals damage equal to the exiled cards mana value to any target
For the black Avatar, it was if there were 10 creatures in all graveyards
Also various reprints have been revealed: Professor's Research (but in Professor Juniper) Air Balloon, Prism Energy, Cheren, Energy Retrieval, Dynamotor Eelektrik
This highly collectible pack was released as a special promotion