> Is there a standard way to indicate that a function returns a new pointer?

No, there is no "standard way" (but there is a policy currently considered "best practice").

Because of this ambiguity ("what does a function returning a pointer want me to do with it?"), it is currently considered best practice to impose the lifetime and ownership policy, through the return type:

 <vertex pointer type> new_vertex(const Options& options);

`<vertex pointer type>` can be `std::unique_ptr` ("new_vertex doesn't own the pointer"), or `std::shared_ptr` ("client code doesn't own the pointer"), or something else, that has clearly defined ownership semantics (for example, `Vertex const * const` would indicate to client code "read the address and values, but change neither/don't delete the pointer").

Generally, you should not return a raw pointer (but in some cases, "practicality beats purity").

**TLDR**: there is a best practice (**yes**), but not a standard way (in the language).