[Balintherlas]

Well here's a list of the books in order:
The Chronicles Trilogy
The Legends Trilogy
The Second Generation
Dragons of Summer Flame
War of Souls Trilogy
The Dark Disciple Trilogy (The third book isn't out yet)
There are also many preludes books about the original companions and they're adventures before the War of the Lance. Also, I believe Weis and Hickman are working on a new trilogy that fills in the gaps of the Chronicles story, the first book being "Dragons of the Dwarven Depths" which is out now.
To the question about Lord Soth he does have his own book it being "Lord Soth" I believe and it is in the Heroes and Villains series. It details his life and how he became a death knight.
There is also the Chaos war series, and Doom Brigade was the first book that I read in Dragonlance.