In addition to the 4 Engine driven pumps there are ADP's on systems 1 and 4 as they are heaviest users, AC motor pumps on 2 and 3 plus additional auxiliary ACMP on system 4 for braking when under tow/maint operations and as an option on system 1 for steering (these are powered by the ground handling bus though so will not be available in flight) slight drift from the original post I think but hopefully informative!