When trying to create a new action, an error appears:
Error! That action name has already been taken.
In looking at the Add Action section for custom actions, no action with this name appears:
If an action is created but left as a draft, it will not appear in the list of custom actions that can be added to a flow.
Actions that are still drafts can be found in the Dashboard by going to Actions > Library and then to the Custom tab.
Actions will only appear on the Flows page to be added after they are deployed.