As the title says. I'm using these alternate class features in my game, and so I've had to convert them to PFRPG at the best of my ability.
Barbarian: Cold Resistance - At 3rd level, the Barbarian gains Cold Resistance 2 instead of Trap Sense. Every 3 levels after 3rd, this resistance increases by 2 points (instead of the regular increase in Trap Sense).
Bard: Specialized Training - The Bard must choose a single category of the Perform skill. When making a performance with the chosen skill, the Bard adds +1 to the save DC of his bardic music effects. In addition, the Bard can use bardic music an extra 2 rounds per day, provided that the additional usage uses his chosen category of the Perform skill. This class ability replaces Bardic Knowledge.
Cleric: Holy Warrior - The Cleric receives proficiency and free Weapon Focus in her deity's favored weapon. Her base attack bonus as a cleric equals her cleric level, and her cleric Hit Die becomes a d10. In addition, she may count half her Cleric level as her level in Fighter to qualify for feats that require levels of Fighter. A Cleric who chooses this class ability gives up both her domains (including all domain spells and powers).
(Note: Made this ability a bit stronger simply because giving up your Domains is more of a sacrifice in PF; did I make it too strong?)
Druid: Mountain Stride - A druid with this ability can move through rocky terrain at her normal speed and without taking damage or suffering any other impairment. Magically manipulated terrain, such as spike stones, affects her normally. This ability replaces woodland stride.
Fighter: War Schooled - A fighter trained at a famous war college or fighting school gains the following class skills (in addition to the normal fighter class skills): Diplomacy (Cha), Knowledge (geography) (Int), Knowledge (nobility and royalty) (Int), Sense Motive (Wis). He additionally increases his skill points at each level to 4 + Int modifier. A Fighter with this class feature must give up either the Armor Training or Weapon Training class feature.
(Note: Sacrificing one feat for 2 skill points/level and a bunch of new class skills seemed too powerful to me, although perhaps this new version is too weak; would giving up Bravery be better?)
Monk: Add Point Blank Shot to the list of bonus feats a Monk can select at any level. Monks of 6th level or higher who possess the Point Blank Shot feat may choose Rapid Shot as a bonus feat.
Paladin: Light of Purity - Starting at 6th level, a paladin with this ability can emit a radiance of blinding light once per week. This light acts like a daylight spell, save that it only lasts for 1 round per level of the paladin. In addition, any undead within 30 feet of the paladin emitting this light takes 1d6 points of damage per round for every two levels the paladin has attained. A Fortitude save (DC 10 + 1/2 the paladin’s level + the paladin’s Cha modifier) halves this damage. A paladin may use the light of purity one additional time per week for every three additional levels he has attained, to a maximum of five times at 18th level. A Paladin who chooses this special ability only gains a Mercy at 3rd level.
(Notes: Really didn't know what to do with this one, to be honest.)
Ranger: Enhanced Companion - Upon gaining Hunter's Bond at 4th level, the ranger must choose to have an animal companion, and must further choose a single type of animal. The ranger cannot call a different kind of animal companion. The ranger’s effective druid level is equal to the ranger’s level – 1 (instead of the normal -3) for that type of animal. This animal must be on the basic list of companions that can be chosen at 4th level and cannot be changed. This ability replaces the Wild Empathy class feature.
Rogue: Poison Master - At 3rd level, the rogue can use poison without any chance of poisoning himself. For every three levels of rogue beyond 3rd, the DC for any poison coated on the rogue’s weapons increases by +1 if the target is poisoned as part of a sneak attack. This ability replaces the Trap Sense ability.
Sorcerer: Hidden Reserve - Starting at 1st level, a sorcerer with this ability can call upon a hidden reserve of magical energy to cast additional spells. This reserve can be used to cast any spell on the Sorcerer spell list (the sorcerer must still be high enough level to cast the spell), but the sorcerer is fatigued for one minute per level of the spell after the spell is completed (if the spell is a cantrip, the Sorcerer becomes fatigued for 1d4+1 rounds). If this spell is of the highest level that the sorcerer could normally cast, the sorcerer is exhausted for ten minutes per level of the spell instead. This ability cannot be used while fatigued or exhausted. It can be used a number of times per day equal to the sorcerer’s Charisma bonus. This ability replaces the Sorcerer's 1st level Bloodline Power.
(Notes: Increased in power to match the increased sacrifice of losing your 1st Bloodline Power; did I overdo it?)
Wizard: Arcane Duelist - Wizards with this ability are specially trained to push their spells when needed to gain the upper hand. When pushing a spell, the wizard can choose to increase a spell’s DC by +1 or add a +2 morale bonus on attack rolls made with the spell, and additionally adds +2 to the caster level check to overcome spell resistance with that spell. A wizard can use this ability a number of times per day equal to his Intelligence bonus. Using this ability is a swift action. A Wizard with this class ability does not receive the Scribe Scroll feat for free at 1st level, and only receives Wizard bonus feats at 6th, 12th, and 18th levels.