Fluvial processes form several channel patterns, including:
Straight, which are found in the most tectonically incised/active areas. This is more of a hypothetical end-member, and are not often found in nature. Straight-type channels can be found at alluvial fans.
Braided rivers, which form in (tectonically active) areas that have a larger sedimentary load than the discharge of the river and a high gradient.