some Gundabad ideas:
Wargs (no riders)
spellbook pwers to fill the two empty spaces:
summon Azog the Defiler
info note below: "So you think his defiling days are done, do you?"
summon Goblin-Town Goblins
info note below: summon 3 hordes of the goblins of Goblin-town Goblins.
a couple Buildings:
(arrow tower; texture could be a hollowed rock with slits for archers)
ideas for maps to include:
Goblin-Tunnels of Moria
hope i helped.