These are some enemies from the Fighting Fantasy gamebooks world which I consider interesting for the game.
Resource: "Out of the Pit - Fighting Fantasy Monsters"BANSHEE
It is said that the wailing of the banshee foretold an approaching human death. Her name is a variation of "washing woman" and it is said that you may see her more often near a river or a lake. PictureCLAWBEAST
A Clawbeast is a large, hairy, mutant creature with four arms each ending in vicious clawsCYCLOP
Savage humanoids instantly recognizable from the large, single eye in the centre of their forehead. As strong as a giant but even more aggressive. The counterpart of barbarians.DEATH WRAITH
They will only be found very close to the coffin of their physical remains for the link between the two is very strong.
They appear as a shroud covered skeletal apparition(beneath the robe there is nothing so they are only vulnerable to magic) with a red-eyed skull wielding the ceremonial dagger part of the treasure with which they were buried.
DEMON BAT (cave terrain)
Ethereal bats whose bodies and wings sparkle with wisps of flame. They usually try to clasp and deliver a massive blast of fire from their bodies (it could be like my suggestion of strapping explosives to worgs and make them blast by clicking several times or like my clickable enemies possessed by Twin Peaks' owls)
They can communicate with one another using ultrasounds, this gives me the idea for a tower to create silence and destroy these whitish sound waves and more 'sound enemies' like cat people howling to attract more feline apes.
People of the jungle who boil and cure the head of their victims on large cauldrons.
They are beaheaders kind of the Blemmyes
that I already suggested:
MIST VAMPIRE (lake terrain)
vaguely man shaped spirit in the form of steam.
He would affect troops and every tower except the mages throwing blue balls, i.e he'd damage soldiers as well as decrease the turrets shots per second.
Enough blue fire causes the mist to precipitate as rain, on the contrary arcane and sorcerer fire increase his size.
Slime loving things who snort poking snots or slimy air by sneezing.
I would like it to be like this human-nose
Like genies but formed from thick black smoke in which a pair of dark eyes glint wickedly.
They hide inside a smoke-grenade launched by orcs with rifle. They could be sort of the hatch Spiderlings, if not killed promptly they join to form a bigger Nanka.
RHINO MEN and WERECREATURE (werebear,wererat,weretiger and werewolf)
It gave me the idea of a new ability for the barrack tower to weremorph your soldies according to battle requirements