These are all monthly subscriptions on Patreon or other monthly accounts. You can also often get these after the release month on sites like MyMiniFactory or elsewhere depending on which company it is.
The order does not reflect my thoughts or specifically the release order they come out. I will be adding to this list and updating as the month progresses.
If you feel you know of a great company doing STLs let me know in the comments and we will see if they can be added to this.
Look for Printers Corner along the top right of the site.