Using only the sets of Bionicle 2015 (so far), Nescent has created a wide variety of Rahi combiner models with detailed descriptions.
Nescent's combiner models so far are categorized into 'Wildlife of Okoto and 'Wildlife of the Ancient City'.
'Wildlife of the Ancient City' documents the Rahi a chronicler known as Teluli finds as he journeys toward the Ancient City, and the chroniclers fate itself.
I felt as though these combiners deserved their own topic due to the large amount, just wanted to address that.
Here are the links to Nescent's 'Wildlife of Okoto' and 'Wildlife of the Ancient City'
Overall, Necent's 'Wildlife of Okoto' gives G2 Bionicle the variety and worldbuilding it needs.