I'm usually looking through rather niche tag groups and more often than not, I have about 80% of the manga already in my library. I think it would be great to simply filter out the ones that are already "reading" or "dropped" or "In Library", for less clutter in search results.
Basically toggle box that checks if title is already in your library, and if it is, hide it from results of "Advanced search".
It probably should put less strain on website than searching through specific library tags, but idk.
mod note: merged into thread