On the new-card side, Shard of the Nightbringer is the one people want, an 8/8 flyer that drains half a players life when it lands, with Biotransference and Their Name Is Death rounding out the flavor-meets-function picks
It doesnt sound like a massive savings, but given the sheer volume of cards youre getting (with 14 in each pack), youre bound to get some very usable ones
Black generally doesn't have very many ways to untap creatures, but you can still work around this to get multiple casts in a turn with cards like Thousand-Year Elixer
That draw trigger isnt just flavor text either
This allows you to bypass the "commander tax," as you aren't casting Derevi and the additional cost will not be applied
This is in order to keep things moving at a reasonable pace and not hold everyone up