These are the monsters which you can easily get by breeding common monsters. There are not too powerful, but can be pretty tough if you train them fully!
Greenasaur
Firesaur + Treezard Elements: Fire, Nature Available in shop: Yes Price: 60 gems HT/BT: 30 secs Rate (lv1): 5 gold/min
Gigram
Firesaur + Thunder Eagle Elements: Fire, Thunder Available in shop: Yes Price: 210 gems HT/BT: 5 hours 30 mins Rate (lv1): 8 gold/min
Flickie
Firesaur + Tyrannoking Elements: Fire, Dark Available in shop: Yes Price: 420 gems HT/BT: 16 hours Rate (lv1): 5 gold/min
Rarawr
Treezard + Gorilla Elements: Nature, Earth Available in shop: Yes Price: 90 gems HT/BT: 10 mins Rate (lv1): 5 gold/min
Utochomp
Treezard + Tyrannoking Elements: Nature, Dark Available in shop: Yes Price: 420 gems HT/BT: 9 hours Rate (lv1): 4 gold/min