Summons to build a strategy around....

[Shovah32]

But against even basic indy priests black servant thugs(which i love) can drop like flies(13 or so MR iirc).

[Lazy_Perfectionist]

It's a bit much for just a thug, but don't forget the Spectral Mage (Summon Spectre, Conj6, 20 death gems). Reasonably affordable for a nation with death income, it's better than a Revenant and Black Servant combined. 25 hitpoints, MR 16.

You can drop the Rod of the Leper King and still lead shades, and use your life drain. Depending on randoms and boosters, you can battle-summon skeletons as well, to 'flesh' out your forces, metaphorically speaking.

[Aleph]

The EA Agartha's Rhuax Pact and... errr... whatever the other one is called. It's a garage sale all the way.

[HoneyBadger]

Another one to really consider building a strategy around is your basic kraken summons-lots of attacks and a tough unit, and fairly cheap. The problem is, they're pretty far up on the research tree. If you can get these guys en masse though, and start casting Quickness on them left and right, you've got an underwater force to be reckoned with.

[Shovah32]

Only 1 level above sea serpents(although early that can be alot). Krakens can, if nothing else, keep you safe until you reach the sea trolls/shark attack combo.

[Crafty]

EA's agartha's Rhaux Pact rocks yes.