4 subsections:
Weak - give frequently dropped items and ordinary skills, they have little life.
Medium - give an average drop and normal skills, they have more life.
Medium/Rare - give an average drop and super-skills, they have more life.
Strong/Rare - give a rare drop and super-skills, they have a lot of life.

Wyverns:
Angel Dragon - Weak, often appears.
Dead Forest Dragon - Weak, often appears.
Purple Crystal Dragon - Weak, often appears.
Candy Dragon - Weak, often appears.
Aqua Dragon- Weak, often appears.
Tide Dragon - Medium, often appears.
Zombie Dragon - Medium, often appears.
Rainbow Dragon - Medium, appears frequently.
Silver Dragon - Medium, often appears.
Forest Dragon - Medium, medium appears.
Imperial Dragon - Medium/Rare, rarely appears.
Blue Neon Dragon - Medium/Rare, rarely appears.
Toxic Dragon - Strong/Rare, medium-appearing.
Devil Dragon - Strong/Rare, rarely appears.
DeadFire Dragon - Strong/Rare, spawned by the administration.

Dragon Monsters:
Magma Beast - Weak, medium appears, you can only kill in the company of 2-3 players or Knockout (skill).
Lava Beast - Medium, medium appears, you can only kill in the company of 2-3 players or Knockout (skill).

Other:
Golden Beetle - Weak, often appears.
Phoenix - Medium, appears frequently.
DeadFire Frog - Medium, spawned by the administration.
DeathSpeaker - Medium/Rare, Medium appears.