Grass-type:

Rose Dragon
Grass -> Grass/Dragon -> Grass/Dragon

Tamandua -> Megatherium
Grass -> Grass -> Grass/Rock

Frog -> Beelzebufo Tribal Chief
Grass -> Grass -> Grass

Horse -> Trojan Horse
Grass -> Grass -> Grass/Steel

Pill Millipede -> Arthropleura
Grass/Bug -> Grass/Bug -> Grass/Steel

Fire-type:

Smoke Magician Rabbit
Fire -> Fire/Fairy -> Fire/Fairy

Horse -> Centaur Knight
Fire -> Fire -> Fire/Steel

Snake -> Ananta Shesha Cobra
Fire -> Fire/Poison -> Fire/Poison

Sheep -> Ram
Fire -> Fire -> Fire/Rock

Calf -> Minotaur
Fire -> Fire -> Fire/Ground

Water-type:

Platypus -> Platypus/Surfer
Water -> Water -> Water

Beaver -> Beaver/Construction Worker
Water -> Water/Fighting -> Water/Fighting

Swan -> Swan/Damsel
Water/Flying -> Water/Flying -> Water/Fairy

Lungfish -> Lungfish/Ichthyostega
Water -> Water/Ground -> Water/Ground

Which one sounds the most interesting?