The best free restaurant bread I've had was at a Brazilian steakhouse, which for those unaware is all-you-can-eat steak.
I believe this was due to their financial incentive of having me load up on bread.
I loved this article, would recommend y'all read it instead of skimming to the end to find the bread
tl;dr
Slices of the cranberry-walnut bread served at Parc, in Philadelphia, and Le Diplomate, in Washington, D.C. Each bite delivers the sensation of eating an entire meal.
Costco's version is pretty dang good!
Now do the best cup of coffee!