Like thick/viscous oil consistency?
I know coolant can have a little oiliness to it and it's usually got a blue tint and dead center front of the engine are the notorious hose clamps that get loose when it's cold. Last summer I put two new clamps in on 1 hose and gave it a nice squeeze after 4 winters of noticing small drips which always required retightening. Last winter was the first time it didn't do it.
I don't think the other fluids in the car have a blue tint, so I don't think it's PS or eGear and definitely not Motor Oil. It could by the hydraulic top fluid, but I don't know what color that is and even if it leaked if that's where it would leak from, though it's possible. Does your top open/close like usual? There is a container for the hydraulic top fluid I want to say behind your seat in the center of that "wall" it's self contained and has no area to leak, unless it's a failed oring or hose though. Also could be from the hydraulic struts... but there really isn't one in the center, just that container with the pump, I believe.