My HV pump on my jeep is rated @ (something like) 9gpm @ 3500. I imagine that there's some limit due to the internal main outlet port size. My Qualcast pump has twice the vane depth of the OEM. It requires hot 20 weight oil to fit the entire volume of the pump output through the engine over the entire rpm range. Anything else slams against the relief.
I would peg the standard oil flow somewhere in the 5gpm range. I gauge this on my own application and stuff like Jeg's aftermarket HV pumps being (or use to) rated at under 10gpm for replacement pumps. Naturally, as OVERKILL remarks, outside of internal design limits of the pump, this would be a function of rpm limits.
..so take into account if you've got a generically OEM common passenger car engine or some ultra tweaked OEM supercar.