I think there is a fursuit database and that also can have character art ref-sheets in it, as well as character name of course. So that would be a way to search for a name not in use, and a suit type not yet made etc. It would be exhausting to do a search like that manually.
I am a generic GSD. The maker of my suit had never made a generic one before, just 2 other GSD types both which were different.
She was allowed to do it because my being generic means I am just an animal, not a copy of a character. If I had unique markings, I would be more of a unique character. However, people can not copy her design because it is hers...
I feel weird about it all. I did ask for a few sewn in markings and they were not made. I also asked for a special air-brush marking also. Also not made. Oh well. And now does it mean no one can be a GSD that is non-marked? I hope not...
So back to the topic, I would try google reverse image search or something like that to scan for images , and fursuit databases. However, for all the fursonas not made into a suit, this gets a lot harder. You almost need a web-service to search it all. I wonder if someone can write such code?