The current doc offers 2 sections [1][2], but they are not complete, remnants remain. i.e.:

These commands don’t appear to be valid in version 1.2 (app label appears to be “codeready”):
oc delete sa -l=app=che
oc delete rolebinding -l=app=che
oc delete pvc -l=app=keycloak
No PVC is created, see takeaway below
oc delete pvc -l=app=postgres
No PVC is creatd, see takeaway below
Leftover resources:
Command: oc api-resources --verbs=list -o name | xargs -n 1 oc get -o name | egrep -i '(codeready|che|workspaces|keycloak|postgres)' | sort
apiservice.apiregistration.k8s.io/v1.org.eclipse.che
clusterrole.authorization.openshift.io/codeready-operator
clusterrole.rbac.authorization.k8s.io/codeready-operator
clusterrolebinding.authorization.openshift.io/workspaces-1-codeready-operator
clusterrolebinding.authorization.openshift.io/workspaces-codeready-operator
clusterrolebinding.rbac.authorization.k8s.io/workspaces-1-codeready-operator
clusterrolebinding.rbac.authorization.k8s.io/workspaces-codeready-operator
customresourcedefinition.apiextensions.k8s.io/checlusters.org.eclipse.che
oauthclient.oauth.openshift.io/codeready-openshift-identity-provider-jnvbl8
oauthclient.oauth.openshift.io/codeready-openshift-identity-provider-rfvcwg
oauthclientauthorization.oauth.openshift.io/A242674:codeready-openshift-identity-provider-jnvbl8
oauthclientauthorization.oauth.openshift.io/A632878:codeready-openshift-identity-provider-jnvbl8
oauthclientauthorization.oauth.openshift.io/A632878:codeready-openshift-identity-provider-pahqd9
oauthclientauthorization.oauth.openshift.io/A632878:codeready-openshift-identity-provider-rfvcwg

[1] https://access.redhat.com/documentation/en-us/red_hat_codeready_workspaces/1.2/html/administration_guide/uninstalling-crw

[2] https://access.redhat.com/documentation/en-us/red_hat_codeready_workspaces/1.2/html/administration_guide/codeready-workspaces_administration_guide#deleting-deployments