71 of the cards date from MTGs Unlimited set, with 30 and 21 copies from the earlier Beta and Alpha sets respectively
Let's jump into this new world
Baral, Chief of Compliance and Defiler of Dreams are premier counterspell payoffs with a free loot and ease of play
There's no direct drawback for you, and lots of upside once you hit delirium
Darksteel was the first "small" expansion to have 165 cards, where as previous small expansions had 143, (with the exception of Legions which had 145 as a balance among the five colors.) The following mechanics first appeared in Darksteel: Indestructible - Mechanic that made permanents indestructible
Unfortunately, it quickly became apparent that building a deck around Vivi resulted in a playstyle that just wasn't much fun, and the card's value quickly normalized