Ford. He ended Vietnam, did what was best for the country despite what the polls said. Of course, I'd call him a libertarian-leaning moderate.
Probably Clinton post-94 would be the second most.
Neither of them were anything approaching "libertarian."
In the relative sense. It's the same as saying somebody is a liberal Republican, they're obviously not liberal, but for their party they are.
Except they weren't libertarian in any sense. They were big government authoritarians.
Is a liberal Republican liberal in any sense?
Ford ended Vietnam and pardoned Nixon.
Clinton reformed welfare, one of the most libertarian bills in a long time.