Currently I think the official LXD packages will be snap packages for all distros, with the exception of the Ubuntu LTS releases.
That is, in Ubuntu 16.04 LTS and Ubuntu 18.04 LTS you get LXD as an official deb package.
Obviously, this does not preclude the distributions from packaging LXD in their own packaging format.
Apart from the AlpineLinux effort to package LXD, there is also a Debian effort, https://wiki.debian.org/LXD