MicroK8S
MicroK8S is the Kubernetes environment from Canonical. It can be setup in a few minutes but isn't as lightweight as K3s. If you set it up on mono node, you will have to deal with the fact that you can't restart the node without losing a part of the cluster or having to set it back up from the ground.
Well i'm not a big fan of MicroK8S, so im biased by the downside i encountered.