The developers (Yanfly and the VisuStella team) are professional programmers who rely on Patreon income to support 20+ hours of coding per week. They have explicitly stated that their old "Full Free" model for RPG Maker MV nearly bankrupt them.
The FREE Cores. Ten of VisuStella MZ's plugins are free to use. These ten consist of the cores for everything else in the library. VisuStellaMZ - itch.io visustella mz plugins full free
Remember to always check the compatibility and terms of use for each plugin before using them in your project. The developers (Yanfly and the VisuStella team) are
: Enhances the battle system with new UI and mechanic options. visustella mz plugins full free