As above, L. Neil Smith's books "The Probability Broach" and "The Venus Belt" are as libertarian as it gets.
Plus, they're hilarious with appearances by odd people like a second-rate house burglar name "Tricky Dick Milhous", and a respected gun expert named "Captain Cooper", along with intelligent Apes and a Coyote with a two gun hat.
Another excellent author is F. Paul Wilson's earlier Si-Fi books, before he went to horror.
His LaNague Chronicles are great. "Healer", "An Enemy of the State", and "Wheel Within Wheels" are all excellent, with "An Enemy of the State" a classic libertarian tale, which was the first appearance of KYFHO.
This stands for "Keep Your F**King Hands OFF".
In Wilson's LaNague League there are two branches of KYFHO, the Flinter's and the Toliver's.
The Toliver's version of KYFHO, is "KYFHO, or I'll move away from you".
The Flinter version is "KYFHO, Or I'll KILL you".
The entire LaNague books were gathered into one volume under" The LaNague Chronicles."