I was looking through the Wiki to check the Epics for each element, as I may sell off some of my monsters to save space.
FIRE:
- Salamander
- Burning Rogue
- Bjarni
Honorable Mentions: Pyrotech
NATURE:
- Ophiuchus
- Primigenius
- Koarim
Honorable Mentions: Cybele
EARTH:
- Primigenius
- Koarim
- Avaast
Honorable Mentions: Growler
THUNDER:
- Kaori
- Volray
- Bjarni
WATER:
- Nautilus-1
- Freeza
- Avaast
Honorable Mention: Volray
DARK:
- Ophiuchus
- Growler
- Postiguraf
Honorable Mention: Burning Rogue
MAGIC:
- Freeza
- Postiguraf
- Teashire
Honorable Mention: Punchie
LIGHT:
- Kaori
- Daganth
- Goathel
Honorable Mention: Wolftagnan
METAL:
- Nautilus-1
- Salamander
- Pyrotech
Honorable Mention: Prototyperion