I have some tunnels created through CLI on several servers locally.
Their domain names are shown in Cloudflare DNS settings as "managed by a cloudflare tunnel".
However, in Access -> Tunnels I do not see their domain names listed.
Are CLI-created tunnels accessible anywhere in their Web GUI?
When created using the CLI, you will see the tunnels on the GUI but not the ingress hosts listed on the config of the tunnel. If you want to get them on the GUI, you will need to migrate the config so that it is hosted on CF. Bear in mind, the migration process is one way only (once hosted, you cannot reverse the process). This shouldn't be a problem unless you're using free TLDs (like .tk .ga .ml ... and the likes) cause all these TLDs are excluded from the CF API and consequently you will not be able to manage them from within the GUI.