Hello,
Minifantasy asset packs don't get monthly updates. Instead, the collection grows by the release of a new main asset pack every month. These main asset packs are released on Itch (like this one).
Minifantasy is a community-driven project. The themes for the monthly packs are all suggested and voted on by the Minifantasy Patreon community.
Besides that, every month I also release Patreon-exclusive add-ons that expand the scope of already-released packs. The exclusive content is also suggested and voted on by the community and it is only accessible to supporters through the Patreon site.
With their subscription, Patrons receive the monthly Itch release + access to all Patreon exclusive content, along with other perks.
I tell you all this so you can see how the new content I make is decided every month, and how and where it is released.
If you have more questions, feel free to ask me.
Have a nice day!