There are some great bigger publishers in the RPG industry but also there are many wonderful small one-man-show-publishers (yes, it's more men than women but we have more men than women in this industry, right?).
My favorite "indie" publisher is Paolo Greco/Lost Pages. It's a small firm located in the UK. Paolo concentrates on old school role-playing but isn't content to re-hash what's been done before but creates new things.
He wrote Adventure Fantasy Game, a simple game which only uses 1d6 and has a unique task mechanism.
Also, Cthonic Codex, a setting book for AFG (here is a great review by Oliof). You can also get this as a boxed set or a coptic bound hardcover. And more.
He uses his own printing services and makes stuff in manual labor. No Onebookshelf and you can really see the quality difference! (Nothing against Lightningsource but the books often don't reach the quality of a good "traditional" printer. Still, it's a good way to go for small publishers.)
Furthermore, he lately pulled in other excellent writers: Chris McDowall, who wrote Into the Odd, an OSR horror-survival game with a unique theme and a great ruleset, and Brendan Strejcek's Wonder & Wickedness, a new magic supplement.
So, if you're looking for fresh ways of looking at old school role-playing you should definitely check it out.
Paolo is also very responsive on G+ and via email and all my packages have arrived without problems neatly packed.