The Preset Sharing section only supports .h9z & .tide formats. I expect that will change at some point. Looks like the ability to add “*.preset” to a forum post came up recently, but I haven’t tried that.
I don’t know if you have used the Eventide EDM application, but (IIRC) there are a few dozen factory presets there, beyond the 5 available onboard presets. Those are also accessible via MIDI Program Changes.