There are knives for everything, big fish, little fish, medium fish, tuna fish, fish filleting, fish slicing, eel, freshwater eel, ocean eel, cutting bones of eel, eel pike, eel whale, fugu fish, octopus, watermelon, pumpkin, cabbage, vegetables, home vegetable knife, pro vegetable knife, etc etc.
In general though, there are 3 main chisel ground patterns.
These are the slicer, either the takobiki, rectangular in shape with a flat edge and square tip, or the yanagi shaped like a willow leaf commonly found in sushi bars. Their most famous use if for slicing fish into sashimi, and there are many variations on these slicers.
There is the butchering knife, the deba, which comes in all shapes and sizes, from the size of a paring knife to over a foot long, and variations for different fish or purposes. It is used to fillet and behead fish, and also used for other butchering tasks. Some are thick, some are thin, some are long and some are wide.
There is the usuba, one has a square tip, and the other has a sheepsfoot tip. Both are dead flat, and are used for the intricate cutting of vegetables, such as the peeling of daikon into a long thin sheet. It is taller at about 50mm to give knuckle clearance, and generally shorter than the slicer.
Then you have your typical western patterns, a few other Japanese patterns you might find though are the gyuto, which is synonymous with a chef knife. The sujihiki which is the same as a slicer. A petty which is also known as a utility. The honesuki, or garasuki, a stiff triangular general purpose boning knife. The nakiri, which looks like a small cleaver, but it meant to cut vegetables, and not bones. Then there is also the santoku, a combination of the gyuto and the nakiri to form a short knife that has a useful tip and a bit of belly to accommodate meat.
There are tons of knives, and its hard to describe them all.