Someone else is already bringing salad.
Something potato: baked or roasted. Grilled vegetables. Bread. And some sausages to grill. Cold cuts to start odd the asado. And lots of wine !
Great, thanks for your response!
I would consider a rice dish - perhaps a Spanish recipe with a bit of "heat" added to it...finely chopped jalapeno perhaps. Red and green pepper and onion dice for some color.
Or you could do similar with corn niblets - adding in the color of the peppers and the "heat" to your taste.
Traditionally the asado is served by itself on a platter, so this should work just fine for a "family style" service or buffet.