There are a number of "special projects" on this site, each dedicated to a specific theme. Some of these special projects, such as those dealing with descendant genealogy, are fundamentally genealogical in nature. Others, such as lists of monarchs, heads of state, etc, are only secondarily genealogical in nature.
Some of these subjects deserve categories as well as lists.
Heads of State and other leaders
Familypedia:Extended discussions
Familypedia:Plymouth Colony - First Families of New England