I can think of Bay Bridge, Richmond, Golden Gate, Dunbarton and another down San Jose way.
Oh yeah, I don't usually think of the Carquinez Straits bridge as crossing the bay -- but it would be a major target.
For number 7 do you mean the one up near Antioch?
I consider those the delta.
San Mateo bridge, which is north of the Dunbarton.
Dumbarton is the bridge furthest south, and would be the easiest to repair. There's no bridge closer to San Jose; Hwy 237 runs south of the Bay, but north of San Jose. San Mateo Bridge is the longest and an important commuter bridge, but would be a dumb target, since all but the high span is only about 30 feet above water, and fairly easy to repair. If the high span were taken out, we'd just rebuild the gap with low-span and forego ship traffic south of the San Mateo.
Golden Gate, Bay Bridge, San Mateo Bridge, Dumbarton Bridge, Benicia Bridge, Richmond/San Rafael Bridge, Carquinez Bridge.
That's seven. Of course, they're ALL covered with pork fat.