Flagellites
Flagellites spend most of there life devouring smaller flaggella. These parasites affect human health and the economy. They are major consumers of primary and secondary productions in the aquatic ecosystem. Eukaryotic flagellates are supported by microtubules. Flagellates are used for propulsion. They can also be used to create a current to bring food. Flagellates also can cause diseases.
Plasmodium
These are highly dangerous protists. If infected with it can cause malaria, though it is usually transferred between humans by mosquitoes. What's cool about this is that the genus contains about 200 species which is divided into several other sub genera. Only about 10 of these though infect humans.
Thallasrasira
This protist was chosen as the first eukaryotic marine phytoplankton for whole genome sequencing because this species has served as a model for diatom physiology studies. It is found throughout the world's oceans.