Essentially, both series present aspects of the unproduced third season of the television series. Arthurian characters are especially prominent in the second arc of the Gargoyles series.
Both comics series have been collected in manga-sized collections and include material that was unpublished due to each series' cancellation. They can be purchased on Amazon.com and direct from Slave Labor Graphics.
I append the details of each collection from the publishers web site:
Creators Greg Weisman, Dave Hedgecock, Will Terrell, Greg Guler, Dustin Evans, Nir Paniry, Karine Charlebois,
ISBN # 9781593620967
UPC Code 9781593620967
Creators Written by Greg Weisman, illustrated by various
ISBN # 978-1-59362-167-4
Diamond Comics Order Code MAY090629
UPC Code 9781593621674
Gargoyles: Bad Guys Volume One
Item Id: bgc1