Quests!

[Tyhm]

All the way up to Sparkly Baddies, Rainbow Baddies and Translucent Baddies, probably. :-P
Well, it'd be easy enough to make a Gray Lizardon using inferior armor, shield and sword...but by the current progression it'd go Gray (2), Blue (3), Red (4), Gold (6), Green (Dragons, 8), White? (10), Black (Lizardons (striped), 12); with the speed boost from Lizardons and the damage boost from Goldwarriors being largely a unique Attribute.

Or conversely, we could say Normal (1-2), Blue (3), Red (4), Gold (6), Green (8), White (10), Black (12) - thus a normal-green Frog is a Normal, a Blue Frog is tougher, a Red Frog is tougher still, a Gold Frog's scary, a Double-Green (either pale or dark) is Lizardon-tough...