Forgot these 6 (plus an additional change). Rogue's Passage is a cool finisher for a deck in the form of a colorless land. Skyscanner and Pilgrim's Eye are cool value fliers for 3 that any deck can use and UW can capitalize on. Golden Egg is a good splashing card or lifegain card. Gingerbrute works in any aggressive deck.
Zacama is another 3 color card that is big, splashy, and fun. I figured to have another 3 color card, make it the opposite 3 color wedge than Sultai that also had green in it (as green is the best at splashing). The card is still powerful if it is reanimated somehow, but is best in Green ramp strategies.

I'm adding 30 cards to the cube for a couple of purposes:

1. It gives flexibility so if another person shows up to the draft, I could in theory draft 9 people.
2. In a standard 8 person draft, it adds a little bit more variation (45 cards from the cube won't be opened instead of 15 cards).
3. More Mana Fixing. Added 6 more multicolor lands to support fixing in the cube so splashing colors is a little easier (hopefully still not the norm). Added the Battle for Baldur's Gate choice gates and Gateway Plaza. These give flexibility. They will be the most powerful lands in the cube, but I still don't think too powerful. We will see if that's true.
4. Support some of the under-supported archetypes:
   a. More support for the gates deck by adding a payoff in both black and white, District Guide to look for a gate, and 6 more gates.
   b. Suspicious Shambler helps UB and GB as it's value from the graveyard.
   c. Release the dogs gives a lot of Go-Wide Power for GW and RW.
   d. Barbed Spike is aggressive, flying, and value after your creature token dies. Should be watched as this is a powerful card.
   e. Inspiration from beyond really helps UB while also being a reasonable Spells payoff in UR.
   f. Curiosity is a great payoff for having fliers. Might be too good with Mischievous Mystic, but it's also so fragile that it's a risk I'm willing to take.
   g. Starlight Snare is a Claustrophobia variant which gives Blue another removal option which it lacked.
   h. Duress is a classic effect, great sideboard card, while being a silver bullet against some decks.
   i. Goblin Boarders can help RG with a cheaper 4 power creature that promotes attacking. Also Goblin.
   j. Spellgorger Weird is a red payoff for spells.
   k. Bolt Bend is a great support card for RG while being decent in other decks too.
   l. Reclusive Taxidermist obviously fits GB best, but it's also just another mana dork that can hit all other colors.
   m. Courser of Kruphix is mostly there for UG, while still being a strong card in other colors.
   n. Universal Automaton is a cheap card any deck can play that gets buffed by any typal lord.
   o. Metalic Mimic is a support card for any typal deck that wants it.
   p. Prophetic Prism supports splashing.
5. Got rid of Inspiring Call and added armorcraft judge since I think the draw on a creature is better than the draw on an instant.
6. Added quick draw dagger to be a cool combat trick that also is equipment over another goldvein pick.

Metalic Mimic helps support typal strategies on the whole. I don't know if I want that, but I don't think this is a particularly egregious card if I do want more typal support.

Boros has two cards I don't really like: Boros Charm and Swiftblade Vindicator. Boros Charm does the aggressive thing in that is just domes a player for 4, but it's modality is severely limited past that. Swiftblade Vindicator lacks a lot of the support to be more than a mediocre two drop (not as many auras or equipment). Either one of these can be replaced with an iconic and simple card like Lightning helix.

There are too many "Make creature Indestructible" Cards in the cube. Taking out Divine Resilience and Offer Immortality to lower that number. Instead, I'm putting in Moment of Triumph, a cheap, efficient combat trick that also has life-gain synergy for BW, and Ransack the Lab, a card selection card that has graveyard synergies for UB and GB.

Impact Tremors is a trap kind of card. It is so bad if not played on turn 2, and it's not the type of combo card that is supported here. Maybe if we added Krenko to the cube, I could see it being better, but for now, I want to put an Impulse draw effect in red to bolster red aggressive strategies and UR spells.

Mana Leak breaks a rule I want to have, which is mono-color cards I add to the cube from outside the Foundations set should not be the best card in your deck. Mana Leak breaks this rule pretty drastically. I am replacing it with Quench, which serves the same purpose in countering spells efficiently in the early game, but giving opponents much more flexibility to play around it in the late game.

Warden of the Woods, while to a lesser extent than Mana Leak, still breaks the rule I presented above. The way how games play out is all about how big threats line up to removal, and the way this big guy just dumpsters on removal makes him pretty quickly become one of the more exciting big green threats. My thought was to use this space to add another card that cared about creatures in the graveyard (the GB identity), which I still think is slightly under supported. I wanted something that rewarded you for having creatures in the graveyard, but wasn't entirely dependent on that to be good. Instead, I will put in Ghoultree. It is feasibly castable in a non GB deck, but only in the late game. In GB you can reasonably get this in play ahead of schedule, and it also is pretty epic when combined with Back for More.

Pirates seems like a trap that doesn't have enough support to make them good. Fynn also seems like it wants to trap people into death touch tribal. I also think elves and spells need some more support, so I'm putting in another Opt and a Elf Token Generator to help push those a little more.

Zul Ashur doesn't really belong here. It's a bad signal card that when you see it makes you think Zombies is a supported archetype, but there are barely any zombies here. It does things I like, but I went with a simple card that supports every archetype I think Black wants outside of sacrifice: Self-Mill (UB, GB), Life-Gain (BW), and is a Vampire (blacks premier type).