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 an additional +1 on attack rolls
 * Favored Resistance I: Gain an additional +2 on saves against a favored enemy

Level 3

 * 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)
 * Skill Athleticism II: +4 on swim and jump checks
 * Skill Stealth II: +4 on hide and move silently checks

Level 5

 * Skill Stealth III: Grants a +5 to Hide and Move Silently
 * Skill Athleticism III: Grants a +5 to Jump and Swim
 * 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)
 * Ranger's Dexterity II: +2 Dexterity

Level 7

 * Skill Stealth IV: Grants a +6 to Hide and Move Silently
 * Skill Athleticism IV: Grants a +6 to Jump and Swim
 * Ranger Action Boost IV: Grants the ability to receive short-term boosts to skills (+9 to all skills), energy resistance (+14), or running speed (5 uses, lasts 20 seconds, cooldown 30 seconds)

Level 8

 * Ranger's Dexterity III: +3 Dexterity

Level 9

 * Skill Stealth V: Grants a +7 to Hide and Move Silently
 * Skill Athleticism V: Grants a +7 to Jump and Swim
 * Ranger Action Boost V: Grants the ability to receive short-term boosts to skills (+11 to all skills), energy resistance (+17), or running speed (5 uses, lasts 20 seconds, cooldown 30 seconds) (note: this enhancement does not appear in the game data files and thus may not be actually implemented)

Unconfirmed
The following enhancements appear in the game data files but their implementation has not been confirmed yet:
 * Elemental Empathy I
 * Extra Empathy II and III
 * Extra Improved Empathy I
 * Favored Attack II and III
 * Favored Damage II and III
 * Favored Defense II and III
 * Favored Resistance II and III
 * Vermin Empathy I