Something like all of them, actually. Seems when they were scrambling around looking for ways to plug in the holes in the tax plan left by giving Collins her $10,000 mortgage deduction and Johnson his 23% deduction for pass-through income (instead of the 17-something in the draft) and the like, they grabbed at a passing hunk of driftwood that turned out to be the cancelled alternative minimum corporate tax and clung to it for dear life.
So in the bill as passed by the Senate over the weekend, the corporate tax, as you'll recall, is fixed at 20%, and there's an alternative minimum corporate tax which as it turns out is also fixed at 20%, meaning Mr. Corporation can decide either (a) to take no deductions and pay that basic 20% rate or (b) take all the deductions he can, but not so as to pay less than the alternative minimum 20% rate.
In short, all your corporate tax deductions will now be imaginary.