Rats:

The radiation caused by the War has caused several breeds of large ferocious rats to appear over the years. Other varieties of rat do exist, but are either unique mutations or rare enough to be dismissed a such.

NB: For the purposes of the Swarm ability, all varieties of Rats count as the same type of creature, the most powerful variant makes the single attack.

Cave Rat (34xp)

Bigger and more aggressive than pre-war rats,

Init III; Atk II; Def II; Resilience II; Damage Save: II; Skills: Acrobatics V, Athletics VI, Sneak VII; Qualities: improved scent, natural attack (bite I), sluggish (–10 ft.), swarm, undersized (Tiny), minion, horde, meek I.

Mole Rat (38xp)

Mole rats are about the size of a dog and have a vicious streak.

Init III; Atk III; Def II; Resilience II; Damage Save: III; Skills: Acrobatics III, Athletics VI, Sneak VII; Qualities: improved scent, natural attack (bite II), sluggish (–10 ft.), swarm, undersized (Small), minion, fearless I

Giant Rat (67xp)

Giant Rats are massive creatures, more than capable of biting clean through an arm of leg.

Init III; Atk V; Def III; Resilience III; Damage Save: VI; Skills: Acrobatics III, Athletics VI, Sneak VII; Qualities: improved scent, natural attack (bite III, Claw II), swarm, Hulking  (Large – 2x2, Reach 1),  fearless I, tough II

 
Radscorpions (46xp)

Radscorpions seem to radiation-evolved versions of Emperor Scorpions, and are common throughout Northern America, their poison is deadly if not treated, though most villages have simple antidotes.
Init  V; Atk V; Def IV; Resilience III; Damage Save: IV; Skills: Acrobatics III, Qualities: damage reduction (3), natural attack (Sting  I, Claw III, Poison III),  minion, tough I,
Neurotoxin: 2d4 rounds, DC16, Drunk for 1d6 minutes; 1d4 rounds, DC18, 1d4 Dex

 
Brahmin (27xp)

Brahmin are two-headed cows and form the staple livestock of the Fallout region, they are much hardier than ordinary cows, capable of surviving on the meagre weeds and scarce water in the wastelands.
Init  II; Atk II; Def II; Resilience III; Damage Save: IV; Skills: , Qualities: natural attack (Trample II), tough I, hulking (Large, 2x1, Reach 1), tough I.

 
Giant Cockroach (Tiny 43xp, Small 46xp, Medium 49xp, Large 54xp)

No-one was survived that cockroaches survived the Great War, those who have encountered the other fauna in the wastes, aren’t particularly surprised a the size some of them grow to.
Init  V; Atk V; Def IV; Resilience VII; Damage Save: VI; Skills: Stealth VI, Qualities: damage reduction (2), natural attack (Bite II),  minion, swarm.

Spore Plant ( 19xp)

Spore Plants are dangerous plants that can spit needles or bite you if you get too close. Fortunately they are rooted to the spot, so aren’t hard to evade if you’re aware of them.
Init  III; Atk III,  Def II; Resilience VI; Damage Save: IV; Skills:, Qualities: natural attack (Bite I),  minion, augmented (blowgun), Immobile (Costed at -6xp).

Deathclaws

No-one knows where the Deathclaws came from, they exhibit qualities of both lizards and mammals are so fearsome that some wasteland scholars suggest they must have been purposefully engineered. Regardless they are the most fearsome living creature you’ll meet in the wastelands.

Baby Deathclaw (Animal — 74 XP):

Baby Deathclaws are yet to reach they’re full maturity (though still nearly as large as a man), though are usually active in hunting roles in a Deathclaw pack, still capable of tearing apart the average raider, and a half dozen can make short work of many wasteland settlements.
Init VII; Atk VII; Def VII; Resilience VI; Damage Save: VI; Skills: Acrobatics II, Athletics IV, Notice IV, Sneak III, Survival IV; Qualities: damage reduction II, fast healing, fearless I,  feat (Wolf-Pack Basics), feral, fleet (+10 ft.), improved scent, natural attack (claw III, bite II), superior attribute (strength +2, dexterity +2, tough I.

Deathclaw (Animal — 125 XP):

A near perfect predator, strong, fast, tough and near fearless.
Init VII; Atk IX; Def VII; Resilience VI; Damage Save: VIII; Skills: Athletics IV, Notice IV, Resolve V, Sneak I, Survival IV; Qualities: damage reduction VIII, fast healing, fearless III, fearsome, feral, fleet (+10 ft.), improved scent, natural attack (claw IV, bite III), hulking(large2x2, reach 2),  superior attribute (strength +4, dexterity +2), tough IV.

 
Intelligent Deathclaw (Standard NPC— 113 XP):

A few groups of Deathclaws have developed to be smarter than average, while only as smart as a somewhat slow human, it gives them certain advantages. These do tend to be slightly weaker, though are still terrifying opponents.
Init VII; Atk VIII; Def VII; Resilience VI; Damage Save: VIII; Competence: II, Skills: Athletics IV, Notice IV, Resolve V, Survival V; Qualities: all thumbs, damage reduction VII, fast healing, fearless II, fearsome, feral, fleet (+10 ft.), improved scent, inferior attribute (intelligence -4), natural attack (claw IV, bite III), hulking(large2x2, reach 2),  superior attribute (strength +4, dexterity +2), tough IV.
 
Other Notes/variants:

Other Deathclaws would be covered by Special NPCs, such as Intelligent Matriachs, or particular characters, translating Intelligent Deathclaw into a racial talent will be “fun”. Maybe limit the specialities to particular racial ones – though can’t think of any particular divisions other than Matriach and Predator.