As Tide mentioned, the list of passive skills in this game are mostly storebought or received from treasure chests. However, some of them are also unique to the two characters in your final party, Guo Jing (who you always control) and Huang Rong (who you don't always control). These two characters are distinct from the temps in that the temps never gain EXP, so they are stuck at that particular level and are stuck with their particular stats. Also, it should be noted that certain passives can upgrade to much more useful skills once their proficiency reaches Lv8. These will be denoted with an asterisk (*)

Storebought/Treasure Skills
Play Dead - Allows the user to escape battle (Useless in the DL)
Hunger* - The user starts the battle POIZN'd
Peppered* - Does nothing
Butterfingers* - When the user uses an item, it is entirely consumed no matter how many items were left.
Scatterbrained* - The user's ATK becomes 0
Sleepy-head* - The user starts the battle asleep
Antidote - Cures one of POIZN
Short-tempered - Slightly(?) reduces DEF
Taunt - Decrease enemy's DEF

Unique Skills
Drink Beer* (Guo Jing) - Slightly(?) reduces ATK
Diplomat (Guo Jing) - Make the enemy run away upon attacking (?%)
Powerful Strike (Guo Jing) - The user's ATK and DEF is raised, triggers upon using an Outer Strength attack (20%)
Supersonic (Guo Jing) - The user's ATK and DEF is raised, triggers upon using an Agility attack (20%)
Meditation (Guo Jing) - The user's ATK and DEF is raised, triggers upon using an Inner Strength attack (20%)
Loudmouth (Guo Jing) - Decreases enemy's ATK
Cheer (Huang Rong) - Increases the ally's ATK and DEF (Useless in duels)
Lullaby (Huang Rong) - Makes the enemy's ATK 0 for that turn

Powered Skills
Satiated (from Hunger) - ATK is greatly raised
Iron Wall (from Drink Beer) - Become immune to physicals I assume for the turn it is used (!!!)
Awakened (from Sleepy-head) - Gain more EXP after a battle
Scavenger (from Butterfingers) - Gain more money after a battle
Memory (from Scatterbrained) - When using either an Inner Strength or an Agility attack, there is a chance it will not consume any Inner Strength or Agility points.
Perseverance (from Peppered) - Recovers Outer Strength, Inner Strength, and Agility points Unique to Guo Jing(?)
Careful (from Short-tempered) - DEF is greatly raised