Ranger enhancements (history)

Level 1

 * Extra Empathy I: Can use wild empathy one extra time per rest
 * Favored Damage I: When attacking a favored enemy, you receive an additional +1 bonus on damage rolls
 * Favored Defense I: When attacked by a favored enemy, you receive a +2 bonus on AC
 * Ranger Action Boost I: Grants the ability to receive short-term boosts to skills (+3 to all skills), energy resistance (+5), or running speed (5 uses, lasts 20 seconds, cooldown 30 seconds)
 * Skill Athleticism I: +3 on swim and jump checks
 * Skill Stealth I: +3 on hide and move silently checks

Level 2

 * Ranger's Dexterity I: +1 Dexterity
 * Favored Attack I: When attacking a favored enemy, you receive a +1 bonus to attack
 * Favored Resistance I: Gain an additional +2 on saves against a favored enemy

Level 3

 * Skill Athleticism II: +4 on swim and jump checks
 * Skill Stealth II: +4 on hide and move silently checks
 * Ranger Action Boost II: Grants the ability to receive short-term boosts to skills (+5 to all skills), energy resistance (+8), or running speed (5 uses, lasts 20 seconds, cooldown 30 seconds)
 * Ranger Desert Lore I: 5 energy resistance versus fire
 * Ranger Tundra Lore I: 5 energy resistance versus cold
 * Ranger Swamp Lore I: 5 energy resistance versus acid

Level 4

 * Vermin Empathy: Grants ability to pacify Vermin
 * Favored Damage II: When attacking a favored enemy, you receive an additional +2 on damage rolls
 * Favored Defense II: When attacked by a favored enemy, you receive a +3 on AC
 * Energy of the Wild I: Grants a 20 point increase to spell points

Level 5

 * Skill Stealth III: Grants a +5 to Hide and Move Silently
 * Skill Athleticism III: Grants a +5 to Jump and Swim
 * Ranger's Dexterity II: +2 Dexterity
 * Energy of the Wild II: Grants a 25 point increase to spell points

Level 6

 * Extra Empathy II: Can use Wild Empathy 2 extra times per rest.
 * Favored Attack II: When attacking a favored enemy, you receive a +2 bonus to attack
 * Favored Resistance II: Gain an additional +3 on saves against a favored enemy
 * Energy of the Wild III: Grants a 30 point increase to spell points.
 * Ranger Action Boost III: Grants the ability to receive short-term boosts to skills (+7 to all skills), energy resistance (+11), or running speed (5 uses, lasts 20 seconds, cooldown 30 seconds)

Level 7

 * Skill Stealth IV: Grants a +6 to Hide and Move Silently
 * Skill Athleticism IV: Grants a +6 to Jump and Swim
 * Energy of the Wild IV: Grants a 35 point increase to spell points
 * Ranger Desert Lore II: 10 energy resistance versus fire
 * Ranger Tundra Lore II: 10 energy resistance versus cold
 * Ranger Swamp Lore II: 10 energy resistance versus acid

Level 8

 * Ranger's Dexterity III: +3 Dexterity
 * Favored Damage III: When attacking a favored enemy, you receive an additional +3 bonus on damage rolls
 * Favored Defense III: When attacked by a favored enemy, you receive a +4 bonus on AC
 * Energy of the Wild V: Grants a 40 point increase to spell points
 * Devotion I: Grants a 20% increase to the effectiveness of your 1st level healing spells

Level 9

 * Skill Stealth V: Grants a +7 to Hide and Move Silently
 * Skill Athleticism V: Grants a +7 to Jump and Swim
 * Extra Empathy III: Can use Wild Empathy 3 extra times per rest.
 * Energy of the Wild VI: Grants a 45 point increase to spell points

Level 10

 * Ranger Action Boost IV: Grants the ability to receive short-term boosts to skills (+10 to all skills), energy resistance (+14), or running speed (5 uses, lasts 20 seconds, cooldown 30 seconds)
 * Elemental Empathy: Grants ability to pacify Elementals
 * Favored Attack III: When attacking a favored enemy, you receive a +3 bonus to attack.
 * Favored Resistance III: Gain an additional +4 on saves against a favored enemy
 * Energy of the Wild VII: Grants a 50 point increase to spell points
 * Improved Devotion I: Grants a 30% increase to the effectiveness of your 1st level healing spells

Unconfirmed
The following enhancements appear in the game data files but their implementation has not been confirmed yet:
 * Extra Improved Empathy I