Clover would be the only one I'd recommend. The seed is fine enough that it will make it thru the sod, somewhat, to get a decent "catch". Cereal grains, like rye, oats, wheat, need pretty good seed to soil contact to work well.
You will have plenty of growing season to get that clover started. We have planted it here very late and wound up with a stand. I must admit, though, that I'm not sure if our little seedlings survived the winter, or if some of the seed germinated the following spring.
The main factor in overseeding or broadcast zero-till seeding is usually getting enough rain to make it go.
did you mow the pasture grass short where you overseeded? Help get as much sun to the seed as possible. The other big threat to your clover is smothering by aggressive grass growth.
Actually the area I want to do is a hill that was barren after building my house. I planted an orchard mix and on west facing side it's taken pretty well with probably 95% coverage. There is some clover, trefoil and crown vetch in the mix. On the southern side it's hasn't taken as well and I only have maybe 60% coverage. That's where I'm looking to overseed. I'm hoping the existing growth will help keep the clover seed in place until it gets established. This will will be perfect since they are calling for cool weather and a chance of light showers every day.