A group of people with similar thinking or beliefs is often referred to as a "cohort," "community," or "like-minded group." In some contexts, they may also be called an "echo chamber," particularly if their shared views are reinforced without exposure to differing perspectives. These groups can foster a sense of belonging but may also limit diversity of thought.
Special-interest groups
A group of people with the same political ideas
One can call a group of people with similar interests 'friends.' One becomes friends with another because they share a similar interest. One can have many friends that share the same interests as each other.
a fleet
Enviorment
Offspring who have the same parents are called siblings.
a religious group is a group of people that have the same religion.
It should be stuck together in a group of gears and the gear module is the same.
A crayfish is a crustacean that has a similar appearance to the shrimp. When referring to a group of crayfish you simply call them by the same name.
uniform
A group of people descended from the same ancestor is a family or a bunch of relatives. Sometimes, if more organized, they may be called a clan or a tribe.
A generation is a group of people born at roughly the same time. A contemporary is someone living in the same time period.