These weaknesses are physical (melee/archer) only, the magics are frequently different.
The conclusion is that the best weapons to have out there are:
AR Slash(/Pierce)
CS Slash/Pierce
AR Fire
CS Cold
When I say CS it means basically non-AR, i.e. could be CB. AR reduces damage on monsters that I've said CS is better on.
Banderling Paragon Fire AR
Banderling Heirophant Pierce AR
Titanium Armoredillo: Slash CS
Drudge Seraph: Pierce CS
Ad. Azure Gromnie: Acid CS
Ad. Ash Gromnie: Cold=Elec CS
Ad. Rust Gromnie: Cold CS
Ad. Ivory Gromnie: Cold=Fire CS
Virindi Profatrix: Slash AR
Virindi Quidiox: Slash AR
Raider Prefect: Cold CS
Raider Justicar: Cold CS
Rev. Tumerok Shaman: Fire=Acid AR
Transcendent Tumerok: Fire=Acid AR
Dark Guardian: Fire AR
Lich Oppressor: Fire AR
Swarthy Mattekar: Fire AR
Dreadful Ursuin: Fire AR
Obiterator: Fire AR
Olthoi Primordial: Bludg AR
Bile Grievvers: Slash AR
K'naths: Pierce AR
Shadows: Slash AR

