Ability to limit download for a specific page or range.
Is there an ability, didn't see it in the "--help" that will allow for the downloading of a specific post or a range of dates. Also, is there a method to test the code to a smaller patreon that has a video link to youtube? (want to see about implementing the ability to call python ala youtube-dl)
No, there is no such feature at this moment.
If you need to check if your plugin works correctly you can do so by checking that your plugin responds to PluginManager.ExtractSupportedUrls and PluginManager.DownloadCrawledUrl when you expect it to do so. The first one is being called on every page and passes each post's html contents, the second one is called on every url which was extracted from the posts and calls IPlugin.IsSupportedUrl on all plugins until it finds the first one which returns true, then it calls IPlugin.Download on this plugin.
I also really want to see such a function. In addition to the date, it would be nice to filter by ID in posts. For example, the link https://www.patreon.com/posts/abc-42886527 creates files when saving 42886527_description.txt and others. It would be convenient to set the saving files from needed ID. Many modern patreons contain posts and attached files for many gigabytes, it is quite tedious to download them in their entirety each time, if only a small part is needed.