Blood is a collective uncountable term, but in the sense of tribes or tribal members, it could be "bloods" -- but this would have very rare and specific uses.
Example:
The chicken coop showed traces of chicken, dog, and cougar blood. (not bloods)
The plural form of "blood" is "bloods."
The plural form of blood is blood.
The plural form of the word atrium is atria. The atria are the two upper cavities of the heart from which blood is passed to the ventricles.
The plural form of thrombus is thrombi.The plural is "thrombi" (from Latin), meaning blood clots within a blood vessel, or in the heart. If a blood clot reaches the lungs, it can cause pulmonary thrombosis.
There is no plural form. Do and Do not are verbs
The plural form of him, her, or it is them. (objective pronouns)
Bridges is the plural form of bridge.
The plural form of "is" is "are."
The plural form of "I" is "we."
The plural form of "was" is "were."
"Groceries" is the plural form of "grocery."
"Beliefs" does not have a plural form, as it is already plural. Beliefs is the plural form of belief.