Values below are for aboveground creatures. PR variants have an additional 60% protection against the basic spells (acid/cold/rot) compared to their normal counterparts.
Animals
arana: 25% acid, 20% rot
arma: 75% cold, 50% rot
bawaab: 75% cold, 50% rot
bodoc: 12% cold, 50% rot
bolobi: 50% cold, 50% rot, 30% poison
capryni: 50% rot
clopper: 50% rot
cray: 50% rot
cuttler: 50% rot
frippo: 50% rot
gingo: 50% cold, 50% rot
gnoof: 50% rot
goari: 50% rot, 30% electric
gubani: 75% cold, 50% rot, 30% electric
horncher: 25% cold, 50% rot, 30% shockwave
igara: 25% cold, 50% rot
izam: 50% cold, 50% rot
javing: 50% cold, 50% rot
jugula: 50% cold, 50% rot
lumper: 50% acid, 50% rot
madakam: 50% rot, 30% electric
mektoub: 25% cold, 50% rot
messab: 50% cold, 50% rot
najab: 25% acid, 50% rot
ocyx: 50% rot
ploderos: 25% cold, 50% rot, 30% shockwave
ragus: 25% cold, 50% rot
raspal: 12% cold, 50% rot
rendor: 50% rot, 30% fire
shalah: 50% acid, 50% rot
timari: 25% cold, 50% rot
torbak: 50% cold, 50% rot
tyrancha: 25% acid, 50% rot, 30% fire
varinx: 50% cold, 50% rot, 30% fire
wombai: 50% rot
yber: 25% cold, 50% rot, 30% shockwave
yelk: 75% cold, 30% rot, 30% poison
yetin: 50% cold, 50% rot
yubo: 50% rot
zerx: 25% acid
Primates
cute: 25% rot
frahar: 25% fire
gibbaï: 25% cold
Plants
cratcha: 80% acid, 25% cold, 30% poison
psykopla: 80% acid, 30% electric, 30% shockwave
shooki: 80% acid, 30% fire
slaveni: 65% acid, 12% cold
stinga: 80% acid, 50% cold
Kitin
kiban: acid immunity, 80% rot, 30% all racial spells
kidinak: 20% acid, 20% rot, 30% all racial spells
kincher: acid immunity, 30% cold, 80% rot, 30% all racial spells
kinrey: acid immunity, 30% cold, 80% rot, 30% all racial spells
kipee: acid immunity, 80% rot, 30% all racial spells
kipesta: 30% acid, 80% rot
kipucka: 20% acid, 20% rot, 30% all racial spells
kirosta: 40% acid, 30% cold, 40% rot, 30% all racial spells
kizoar: 25% acid, 80% rot
kizarak: acid immunity, 80% rot, 30% all racial spells
Mobs which only exist in PR variant:
Vorax: Immune to all basic spells, 40% all racial spells
Jubla: acid immunity, 60% cold, 60% rot
And that concludes what's probably the last list in the series, magic resistances would just be too much of a pain to try documenting
