Hi, I am glad you like my plugins 😁!
I would like to make demos for all of them, it is just something that I do not have the time for as I am only one person supporting 100+ plugins. Demos for paid plugins also have extra work that goes into it because I need to figure out what I can cut out for the demo version and do additional testing on the demo version. I tend to make demos for my plugins once they are fully released, just don't have the capacity to do it for every plugin.
I do have a wiki (started at the end of march, so still a bit of a work in progress) where you can see all of the plugin commands + parameters that each of my plugins have to get a better idea of how customizable something is or what you can do with it before buying.