I'm from Scotland, so naturally, take what I say with some salt.
1. One thing I've often heard is that if you're skinny enough, you can shop the kids section and they will have plenty for you to work from.
2. It's best to narrow down specific terms/phrases when using the Internet to find clothing. Emo, Grunge, Y2K and so on are a great start, but you should also try Tattoo Grunge/Mesh, Rhinestone, Striped, etc.
3. There's plenty of Alternative brands out there, all you need is a bit of imagination and thinking outside the box. If you see something you like, there is always a way to make it work. No matter what.
4. Have a Pinterest board and just go nuts. Not only will some of the images come with brand names or links, but it'll give you a good idea of what it is you're looking for.