The official solution for what I am looking for is SwaggerHub.
What I like about these solutions is that they are free and python based.
I would like to be able to use SwaggerHub, but I simply do not have the funds to do so.
Are there any other popular and well-maintained python based solutions that I could consider?
SwaggerHub is a collaborative platform for API design, it's not a server application to run your API.
The other two projects that you shared are actual code libraries you can use with/for your application.
I can't speak for those libraries as I'm not a Python developer, but I know that https://github.com/zalando/connexion is a well-maintained project you may want to consider.
If not SwaggerHub, then what other product or open source project ( https://swagger.io/tools/open-source/ ) would it be, if any?
The list you're referring to is there just to help find available projects, and it's far from being complete.
None of the items on that list is official.
The Swagger (and now OpenAPI) Speficiation is now managed by the Linux Foundation under the OpenAPI Initiative (OAI) organization (openapis.org). As a rule, the OAI does not endorse any specific project as an official one and does not directly deal with implementations.
So as far as it goes, there's not going to be an 'official solution'. It's up to you to choose the tool that fits your needs best.
What also seems to be a popular solution, solving the same problem as FastAPI or Connexion or django-rest-swagger is Springfox ( http://springfox.github.io/springfox/docs/current/ ) ... of course, Springfox is Java based.
What I am having trouble determining is which of these are the most complete, best maintained, etc.
If anyone has any input with respect to this, I would be interested. Having this discussion will help clear up whatever confusion I still have concerning the swagger / OpenAPI space in general.