Here is the list of things you'll need to create. Note that some of these elements can only be created in the 4th episode, so don't panic if you complete the first episode and you don't get the achievement.
Episode 1:
Ghost
Dragon
Golem
Zombie
Ghoul
Vampire
Werewolf
Phoenix
Thunderbird
Treant
Episode 4:
Darkness
Shadow
Underground
Demon
Death
Chaos
Alternatively, you can consult a complete walkthrough here:
http://ayumilove.net/doodle-god-walkthrough-guide/