Shadow, Mysterious Assassin* The Final Fantasy 6 Commander Deck version of Shadow is a decent enough creature, but deathtouch isnt a great evasive ability and to make the best use of his ability he really needs to get in so you can sacrifice whatever permanent you sneaked in for cards and damage
Likewise, foils are going to start very, very high, and retrace only 30-40% as peak supply rolls through
Let's lump them all together out of respect and get to the real chonkers: Polar Kraken Denizen of the Deep Spawnsire of Ulamog Darksteel Colossus Inkwell Leviathan Titanoth Rex It That Betrays Blightsteel Colossus #26
Some folks sell custom sets or run Kickstarter campaigns for entirely new expansions
The bonus cards this time round arent super impressive
Mono-black ramp packages should be built around the Coffers engine: Cabal Coffers, Urborg, and 2-3 Swamp-scaling payoffs like Crypt Ghast and Magus of the Coffers