I don't know how about you, but I am sure that the best graft for brawl mode is "Terrid Clone". What this item does, it plays the first card each turn, twice.
I think that is the best graft in all griftlands, playing your first card twice, means that you can get double defense from portable bunker (30*2 = 60 defense!) and essentially, it gives items that had only 1 usage left, 1 extra use! That means that that card you get from Joe the drone assassin, which sum ins 1 drone, will sum in 2 drones for the fight. So does the card that you get from the robot fight, with a funeral auto dog. Then the attacks, you can use kicks that normally deal 8 damage, to deal 16! The problem that I have with this graft is that other grafts from brawl mode, seem too small in compression with it! If you use any other graft for brawl mode, let me know how and why!