Black Diamond is pretty much synonymous with carabiners, or whatever that thing is where one word makes you think of another: Black Diamond makes me think about biners, and biners make me think about BD. That's just the way it is. This true, probably, because Black Diamond makes some of the most trusted carabiners out there, and it's pretty important to trust your biners.
Basically, Black Diamond makes all your standard types: locking carabiners, light weight biners, easy cleaning biners, straight gate, bent gate, and wire gate. Plus, D carabiners, and oval carabiners. So you can mix all that, too. Want a wire gate oval carabiner? Black Diamond makes it. Or a locking D carabiner? BD has that, too. See where I'm going with this? What it comes down to, though, is that Black Diamond biners are a must for your rack. Just sayin'.