a decent ability: the gremlins' repair skill, which is especially useful in duel mode with Razazak. Fairies are also very good: they attack all adjacent creatures without retaliation, like a wasp swarm. But still, level 1 isn't a walk in the park, so skeletons are also good (there are a lot of them).

Level 1 isn't a walk in the park at all! You need to protect some creatures, otherwise you won't steal much mana from the enemy, you won't be able to repair many golems, and you won't be able to poison them much! Even goblins, the weakest creatures in the game, can surprise the enemy with their traps!
But level 2 is where the real cannon fodder is. Especially gargoyles, zombies, dancers, and those... what are they called... anyway, horned demon things. The latter are completely useless. Dancers and furies die like flies by the middle of the game, as the computer only tries to get them with overwhelming force!