[Whether you love the way they look, if you love to fight them, or whatever]
Here is the list:
Albinoid
Alexia: 1st Form
Alexia: 2nd and 3rd Form
Bandersnatch
Bat
Birkin G-Mutation
Black Tiger
Brain Sucker
Cerberus
Chimera
Cleaners
Crimson Heads
Crocodile
Crow
Dr. Salvador
Drain Demios
Eliminator
G-Type
Garrador
Giant Bat
Giant Centipede
Giant Moth
Giant Spider
Glimmer
Grave Digger
Gulp Worm
Humanoid Leech
Hunter
Hunter 121 Beta
Hunter 124 Gamma
Hypnos Tyrant (Type I)
Hypnos Tyrant (Type II)
Hypnos Tyrant (Type III)
Iron Maiden
Leech
Licker
Lisa Trevor
Los Ganados
Lurker
Morpheus (1st Form)
Morpheus (2nd Form)
Mr. X (Tyrant-00)
Mutant Plants
Nautilus & Torpedo Kids
Nemesis
Neptune
Nosferatu
Plant42
Pluto
Queen Bee
Queen Leech, 1st Form
Queen Leech, 2nd Form
Roaches
Sliding Worms
Spiders
Stinger
T-Veronica Mutant
Tyrant-001 (Prototype Tyrant)
Tyrant-002
Tyrant-003
Tyrant-078
Tyrant-091
Wasps/Halbert
Yawn
Zombies
Alexia: 1st Form
Alexia: 2nd and 3rd Form
Bandersnatch
Bat
Birkin G-Mutation
Black Tiger
Brain Sucker
Cerberus
Chimera
Cleaners
Crimson Heads
Crocodile
Crow
Dr. Salvador
Drain Demios
Eliminator
G-Type
Garrador
Giant Bat
Giant Centipede
Giant Moth
Giant Spider
Glimmer
Grave Digger
Gulp Worm
Humanoid Leech
Hunter
Hunter 121 Beta
Hunter 124 Gamma
Hypnos Tyrant (Type I)
Hypnos Tyrant (Type II)
Hypnos Tyrant (Type III)
Iron Maiden
Leech
Licker
Lisa Trevor
Los Ganados
Lurker
Morpheus (1st Form)
Morpheus (2nd Form)
Mr. X (Tyrant-00)
Mutant Plants
Nautilus & Torpedo Kids
Nemesis
Neptune
Nosferatu
Plant42
Pluto
Queen Bee
Queen Leech, 1st Form
Queen Leech, 2nd Form
Roaches
Sliding Worms
Spiders
Stinger
T-Veronica Mutant
Tyrant-001 (Prototype Tyrant)
Tyrant-002
Tyrant-003
Tyrant-078
Tyrant-091
Wasps/Halbert
Yawn
Zombies
Feel free to choose more than one if you are indecisive!