The functions that I really need the most is to press shift to zoom the images without entering them, infinite scroll and “subscriptions” and I have been researching scrips but I have not been able to find any that perform similar functions.
I can see why there isn't anything. There isn't much of an api to work with in comparison to 621. https://api.rule34.xxx/ vs https://e621.net/help/api Unless there is an API I'm not seeing. The whole link format is query string stuff. I don't know why if your running a site like that you don't just use danbooru as a code base.