Following an interesting discussion in the comments under How can I set cookies on my posts so that I can get view count of that post I'd like to know if plugins hosted on wordpress.org are considered third-party in the sense of the WPSE guidelines where you won't receive support for them here? Or if they are considered somewhat different, if not first-party?
Taking Post Views Counter for example as this was the subject in the mentioned question above I'd consider this much more of a first-party plugin (and therefore on topic) than any (premium) plugin that's hosted somewhere else, for example MemberPress. If a user would have problems with Post Views Counter on let's say how to programmatically query posts by view count I'd consider this on topic.
Regarding Drupal there is the division between core modules, contributed modules (hosted on drupal.org), custom modules, and third-party modules/libraries (hosted somewhere else then within the Drupal infrastructure). But only a really small percentage (if not none) I guess is offering additional premium features.
Or is this distinction for WordPress a little bit more difficult? Since a lot of lite versions of plugins are hosted on wordpress.org which let you subscribe to additional premium features/add-ons like for example Yoast or WooCommerce?