I've used runc, which worked out well for me, but it's not a "drop-in replacement" for everything Docker does; it's essentially just an OCI runtime (originally extracted from Docker I believe), but 9 times out of 10 that's what I want.
There are other tools too, such as containerd (and more I don't recall the name of first-hand), but I don't have first-hand experience with them.
There are other tools too, such as containerd (and more I don't recall the name of first-hand), but I don't have first-hand experience with them.