Wikipedia lists the names of 18 confirmed canon Skeksi, some only seen on Netflix and the canon novels. skek-Ung who wasn't in the prequel series becomes the Garthim Master and 2nd General and is said to be the strongest of the Skeksi after the original Emperor. The Chamberlain for all his scheming is most of the time the heir to the throne, but seems to constantly clash with the Generals of both the movie and TV series, lol.. and ultimately lost the battle for the throne when the decaying Emperor died. The Ritual Master politically speaking seems to be fairly high in the pecking order as well.
And, the Heretic was a goofy highlight for me, lol … For all the darkness any follow up material has to have, with the Garthim War and genocide, they need to explore the Mystics a bit more. With the exception of The Archer, they've all been pretty forgettable.