I am including the Jace, Architect of Thought I pulled just because it is a very strong card. I don't think it is a great fit for Grixis, but still, this card is a bomb.
Dimir (Blue/Black Guild) comes out in the next set (Gatecrash), and although there are several Dimir cards in the ISD block, the only one that I think fits Grixis is Evil Twin.
I do have one each of the shock lands for Rakdos and Izzet. I need a Dimir shock land from Gatecrash.
Here is a McLand from Magic 2013.
And I have play sets of the Rakdos and Izzet guildgates.
I also have a playset of Stensia Bloodhall in this mini cube.
Running three colors in a casual build requires play sets of several utility lands, all in this mini cube.
I have a pair each of the Rakdos and Izzet keyrunes from the theme decks.
In order to be able to survive a long game, I am planning to add life with several artifacts. Here they are.
In case I play against a casual curses deck, I need Witchbane Orb in my sideboard.
Here are additional artifacts.