https://images.opsmaru.dev/ - not sure if its free to use.
lxc remote add opsmaru https://images.opsmaru.dev/spaces/b82cb0551bccd5edb7cf8626 --public --protocol simplestreams
lxc profile show default | grep security.nesting
https://images.linuxcontainers.org/images/ - Rip dead.
LXC belongs to canonical now so only ubuntu will work.
https://cloud-images.ubuntu.com/releases/ - This is what works.
lxc remote add lxc https://mirrors.tuna.tsinghua.edu.cn/lxc-images/ --public --protocol simplestreams
lxc launch lxc:archlinux/current archlinux
lxc remote list
https://blog.skihome.xyz/archives/4/
lxc remote add lxd-canonical https://images.lxd.canonical.com --protocol simplestreams --auth-type tls
lxc launch lxd-canonical:archlinux archlinux1