This is the result of around a week of work combining the Toa Mata with their respective Bohrok counterparts into a rahi each with a function and kanohi on their body. One of these is my interpretation of a canonical rahi that lacks art or a set form, with only a description to go off of.
This is the result of combining Tahu with Tahnok. The Manahi, a fiery ostrich with a strong neck, perfect for driving its face directly into another being, or into the ground. It bears its kanohi on its chest.
Instruction video link: https://youtu.be/syqraRFA7OQ
The combination of Lewa and Lehvak. The Kowa Jaga. The jungle dwelling variant of the Nui Jaga, sporting a single kanohi on its right claw, with a standard left claw. Its tail end resembles an axe blade, and strikes in a diagonal upward/outward motion meant to attack larger predators/prey than itself.
The combination between Gali and Gahlok. The Makuta Fish. Described by Matau as a fish with the same happy-smile as Makuta, with rows of teeth, and who's bones Nokama turned into her trident. It only made sense to make this particular rahi blue, since Nokama's trident is blue. It bears its kanohi on its back, and has a tail slapping function. The first image doesn't include the simple stand I made to prop it up, the pieces of which don't come in either Gali or Gahlok.
The combination of Kopaka and Kohrok. The Kokiore. A mouse-like rahi with a nasty bite, and the ability to turn inside its own skin, this rahi is considered a pest in the icy regions it inhabits, as it often chews on large ice structures, causing sculptures to topple, with the occasional chance of causing an avalanche. It bears its kanohi on its rear.
The combination of Onua and Nuhvok. The Nurati. A rabbit-like rahi with a powerful leaping function, it often burrows in the depths of mountains to avoid the majority of its predators. This rahi's eyes provide it with excellent infrared vision, with small organs producing slight infrared light within the vast dark underground. Its mouth is located on the underside of its face, allowing it to look ahead while eating the roots it digs for. It bears its kanohi on its tail.
And finally, the combination between Pohatu and Pahrak. The Nakaraha. A cobra-like rahi that dwells in the desert, slithering under the sand to stalk its prey, powerful muscles located in the neck area allowing it to snap its head out of the sand to deliver its bite quickly. These rahi are known as the desert phantoms, able to fell an entire Mahi herd without being seen. Rattles located in its tail are used to detect even the slightest of tremors in a large radius of barren sand, a problem during a sandstorm. When sandstorms do occur, these rahi become exceedingly agitated, becoming a danger to matoran wandering in the area. It bears its kanohi on its upper back just before the location of the rattles.
I hope you enjoyed the backstories I came up with for the majority of these rahi, barring the makuta fish. I made sure each rahi had a kanohi and function (Although most are just the bohrok function, with the makuta fish also being the exception in this case coincidentally) since I believe good rahi design should incorporate a function and a kanohi located somewhere on the body. Barring those criteria, rahi are still okay as long as they look like they could be a functioning, living creature like the kikanalo or energy hound.