[shoukosumeragi]

Since I've run into this question quite  a few times myself, I thought I'd make a list for reference. These are no way, well some might be, the absolute required nature, but more of a guideline. This is a work in progress and any help/tips/suggestions are appreciated. Thank you. 

Please take abilities in consideration when deciding nature.

ANCIENTS

Albinus - Profound
Anglare - Hallucination
Arbogon
Arctle - Tank
Aturion - Trembling
Augurix
Aurorile - Hallucination/Tank
Chlorotops
Chromaul - Butcher/Reaper
Cielon
Cragantula
Decesile
Dracorpio
Drakosukus
Drausoleum - Tank
Egypri - Butcher/Reaper
Erdegon
Fendark
Gigerath - Hallucination
Gigoliath - Hallucination/Tank
Golemet - Butcher/Reaper/Profound
Goritaur - Profound
Grasilisk - Tank
Grythin
Hetephinx
Hyreigna
Ionoule
Jaghoul - Tank
Jolteta
Korrodo - Trembling/Butcher
Korrosvat
Mastice
Midandr
Odonasma
Orogond - Trembling
Prysma - Butcher/Reaper
Qillusion - Profound
Quinnlong - Tank
Raijunder
Sarcuda - Profound
Serperor
Stromeleon - Hallucination/Tank
Submakarb
Tempteras
Terrabbit
Ugoyle - Butcher/Reaper
Vesuverex - Tank
Vydral - Tank
Wargile - Hallucination
Xwartya - Butcher/Reaper
Yatagarasun

LEGENDARIES

Alaclipse 
Arxon
Chesshot
Chimeros
Dimagem
Divawn
Dragonoon
Duskami
Freezaco
Gargravel
Haloudelou
Hulkapow
Icebragled
Jawguile
Kelvice
Kuraigon
Lunardian
Mantice
Meteoid
Miroushon
Mythulu
Nightheos
Ookichia
Pegurush
Polnorso
Reptide
Rubtilia
Solord
Spiralaxy
Steeleon
Stellack
Tsunidle
Veptis
Volcaurus
Wolverazor
Zonench

ZENITHS

Absoliutus
Aister
Alieian
Alta
Aquayro
Arizox
Astrum
Auramus - Profound
Bavante
Behemoth
Betamma
Blazero
Blobelisk
Brachpour - Tank
Buffampede
Bunda
Caesidote
Cerebrain
Chillurk
Chromeleon
Coroneon
Dinothorn
Dracoflare
Draconight
Dractanium
Dragoscorch
Drakell
Eion
Engiron
Falcoflame
Felri
Furrage
Futairik
Gampha
Garubitic
Gilizar
Glamvas
Graero
Grawsora
Griffix
Gryvolt
Harpiros
Heatora
Helion
Herophoenix
Houndeath
Iitiyel
Invion
Jetegin
Jrava
Kaokung
Khanwhibon
Killipede
Kuraimi
Leonior
Lumenoth
Lunarikon
Magnilok
Mandroh
Mantyrant
Marocepter
Mestaccato
Monason
Moosnow
Moskarade
Moundible
Namagon
Nrakros
Obsighus
Plagubonic - Profound
Potasinite
Psyrox
Psywar
Pyrake
Quensea
Rabblade
Ragarock - Hallucination/Tank
Reven
Roivile
Salaritian
Serpensiris
Shellion
Socilec
Solarikon
Sounore
Sounvern
Spectrorb
Spidermon
Talight
Televitate
Trampolm
Ursaze
Visiood
Warong
Warrox
Wilitus
Xenomonster
Yetee - Profound
Zeknair

Special thanks to these contributors
PupK9
Qurac23
Alduin