The largest I have heard of (& seen) were 13 puppies, all survived.
From an orange roan bitch. This was a few years ago, I think the same bitch has since had another big litter of 10 or 11, can't remember now.
My largest litter has been 7 puppies, had a few of those.
Funny but Parti-colours tend to have bigger litters than solids, on the whole.