Menatus looks pretty cool, the torso and weapons are quite unique. He is a bit on the skinny edge though, and I think the Bohrok eyes should be "pinned" in the center and extend to the sides, not the other way around.
Tarkah looks pretty cool. The blue hands and trans-green on the forearms are a bit out of place, though, and he might benefit from having red spikes on other parts of him.
Zestrox is decent, his torso seems to work a bit better than Menatus, but the claw elements break the color scheme, as do the black armors on the thighs, and (to a lesser extent) the gunmetal shield. I know tan is hard to come by, but if you could, use only a single secondary color.
Travach is okay, don't quite like the legs, or the tube on his chest but he has a bit more character than the mainstream black-and-silver MOCs. Double spear looks cool too.
Cyalite I don't quite like, the bulky torso and thin legs don't match well, and the grey feet are really off from the rest of the colors. Replacing the trans bright green with trans orange could help as well.
Overall, a nice starting batch of MOCs.