It's no small statement to Synth1's power that there are thousands of presets available in the wild, but there are so many that it's essentially impossible to navigate them all. Synth1 Librarian has done much to tame this powerful beast, and to bring those thousands of presets within useful reach.
On top of all this, the developer NeutrinoSky donates all proceeds from donations to the project to worthy causes. Download, use, and donate. There's no downside here. A great project to contribute to.
This review was edited after recieving a message from the developer to clarify a few points.
I am critical of the requirements to download, which involved an elaborate set of social media steps which weren't outlined here. It seemed to be unreasonable given that the requirements weren't disclosed here.
The developer informed me that there's a way to truly download the plugin for free without having to follow those social media requirements, although it's not clear on the plugin page.
Coming back to download and evaluate, it appears the posted download restrictions remain the same, with no clear way to obtain the plugin.
The real problem is that it's represented as 'free' but the user has to jump through hoops to get it.
Perhaps one day if the plugin is offered without any hassle, with a "download" button on the page, more users will be able to evaluate the product.