Is there a GWG article that lists species and what they are resistant/weak to?
e.g. Monster x is weak against piercing, resistant to fire
Monster y is ...
Guildwiki is not very helpful, GWG search turns up nothing.
Bestiary: including monster resistances/weaknesses
Perfected Shadow
Commander Ryker
Not to my knowledge. I've never seen anything like that.
Savio
If you look at the specific damage types at [wiki]Damage type[/wiki], you can see what some species' weaknesses and resistances are. I don't know how comprehensive it is, but it's a start.