Buddy is a Autcraft rank. A player who has Buddy rank will have the word Buddy in green in front of their username.
How to become a Buddy
The rank is earned through being nice to other players and helping them out.
Buddy gives you access to /fix, /heal, /feed, and /craft (or /wb, or /workbench) and a permanent teleport timer bypass to help other players more easily. Also, they can /feed and heal others.