Azwan.

STR: +1~40.
DEX: +1~40.
INT: +1~40.
LUK: +1~40.
Accuracy: +10~400.
Avoidability: +10~400.
Weapon DEF: +10~400.
Magic DEF: +10~400.
MaxHP: +15~600.
MaxMP: +15~600.
Jump: +2~20.
Speed: +2~20.
Weapon ATT: +3~30.
Magic ATT: +3~30.
Critical Rate: +1%~30%.
All Stats: +1~40.
Attack Speed: +1.
Weapon DEF taken from Magic DEF or vice versa: 1%~10%.
MaxHP taken from MaxMP or vice versa: 5%~50%.
Amount taken from one stat and put into another: 1%~10%.
(^Only works for STR <-> DEX, INT -> LUK, DEX <- LUK)
Accuracy: +1%~+20%.
Avoidability: +1%~20%.
Weapon DEF: +1%~20%.
Magic DEF: +1%~20%.
MaxHP: +1%~20%.
MaxMP: +1%~20%.
Accuracy: +1%~10%.
Avoidability: +1%~10%.
Bossing Damage: +1%~20%.
General Damage: +1%~10%.
Attacking Damage: +2%~20%.
Instant Death: +1%~+10%.
Abnormal Status Resistance: +1%~+10%.
Weapon/Magic DEF -> Damage: +3%~+50%.
Damage Ignore: +1%~10%.
Cancel Cooldown Chance: +1%~20%.
Passive Skills Level: +1.
Amount of Enemies Hit: +1.
Buff Duration: +2%~50%.
Drop Rate: +1%~20%.
Mesos Rate: +1%~20%.

These are the possible inner abilities according to shakar's old blog post.