* Phylum Sarcomastigophora: This phylum includes amoebas, which move using pseudopodia, and flagellates, which use flagella for movement.

* Phylum Apicomplexa: These are parasitic protozoans with a complex life cycle, often involving multiple hosts. Examples include Plasmodium, the causative agent of malaria.

* Phylum Ciliophora: These protozoans use cilia for movement and feeding. They have complex structures and can be found in a variety of aquatic environments.

* Phylum Microspora: This phylum comprises obligate intracellular parasites that can infect a wide range of hosts, including humans.

While these are the major phyla, there are also other phyla that are less commonly studied or accepted, such as Phylum Myxozoa and Phylum Ascetospora.

It's important to remember that the classification of protozoans is constantly evolving, and new information may lead to changes in the established system.