The novels
A Time to Kill by David Mack and
A Time for War, a Time for Peace by self have a great deal of Klingon politics in them. (The book between them,
A Time to Heal, also by Dave, is certainly worth reading, but has very little Klingon in it.) There's more in
Articles of the Federation, though Klingon stuff is only a part of the wider tapestry of that novel.
The Lost Era: The Art of the Impossible, also by me, chronicles an 18-year conflict between the Cardassians and Klingons, and includes (among other things) a dramatization of the Khitomer Massacre.
You say you've read the
Gorkon books, but have you read all of them? There's the TNG novel that introduced the ship,
Diplomatic Implausibility; there's the crossover duology
The Brave and the Bold, which features Klag and the Gang in Book 2; there's the three books under the
I.K.S. Gorkon banner,
A Good Day to Die, Honor Bound, and
Enemy Territory; and then there's the
Klingon Empire novel
A Burning House.
For 23rd-century Klingony goodness, there's
Excelsior: Forged in Fire by Andy Mangels & Michael A. Martin, which is the prequel to "Blood Oath."
If you're into comics, I strongly recommend the five-issue miniseries (also collected into a trade paperback) from IDW
Blood Will Tell by Scott & David Tipton and David Messina. There's also an
Alien Spotlight: Klingons one-shot coming later this month by me and JK Woodward.
That should keep you going.
. They are excellent, and I highly recommend them all. You should also check out the IDW Klingon mini-series from 2007. Also a great read, and the art is beautiful.
