Questions says it all, really. What are the big Game Systems and Publishers out there that are non-d20/OGL, and not D&D? I'm trying to broaden my horizons in gaming and I'm looking at the big companies and system. Note, I'm not talking about single product RPGs, here, but rather those companies like White Wolf that release loads of support for their products.
Exalted by White Wolf is a very significant one.
It's often overlooked by this kind of list, which is insane, because according to WW, it's one of their best sellers, and it's got huge support. It's a extremely high-magic epic fantasy game, where, by default, the players are Solar Exalted, beings of incredible power come to reclaim their "birthright". Obviously many other beings in the setting are not keen on them doing so, and it's a curious combination of Wuxia, Indo-European Myths and JRPGs (with a little too much "anime" mixed in for my personal taste, but at least it's explicit).
As for Vampire, Mage, Werewolf, Promethean, Changeling and the upcoming Hunter, yes, they ARE all based on the same system, indeed they share a central "system book" called
The World of Darkness, and are in fact designed on the basis that you can use content from one of them with the others without having to try to "adapt" it or the like.
They also have Scion, a game of being the children (scions) of ancient gods in the modern day, which somewhat rocking. I don't think it'll see much further support, as it was designed specifically as an "arc" product, releasing three core books then stopping, but it's recent and decent (I don't love the system, personally, but the ideas are good).
I don't know if you want on include RPGs that have a lot of support already but aren't like to see more.
Cyberpunk 2020 is one such. It was huge fun in the 1990s, I can tell you, but it can seem a little dated today. It's still in print and it's supplements are usually available, however.
Shadowrun is a system that's still going, still seeing new editions and new supplements. It's future-set game where magic has returned to the world (in full force), and so have various mythical races (with some of a Tolkien-esque bent).
More later perhaps, as even everything mentioned is far from all there is.