How many different types of consumers are there?

How many different types of consumers are there?
There are usually three or four levels of consumers.

There are primary consumers who eat plants.
Secondary consumers eat the plant eaters.
Tertiary (third level) consumers eat those meat eaters.
Quaternary, or fourth level, consumers eat the third level animals.

The tertiary or quaternary level consumer is usually the 'top predator' at the top of the food chain. Nobody kills and eats the top predator. They die of disease, accidents, old age or fights.