Broadly, there are four different categories of theological works.
Biblical Theologies: Present theological material in a way that reflects those of Biblical books; pays attention to the way words, themes, and concepts unfold throughout Biblical history and in the Biblical canon.
Systematic Theologies: Present theological material in a systematic way based on defined categories (eg. the nature of salvation, God, the work of the Spirit, etc.)
Historical Theologies: Present the ways Christian theology has developed throughout church history and across different traditions.
Contextual Theologies: Present theological material in a way that puts the Bible and church tradition in conversation with the issues and questions of the theologian's context (e.g. Postmodern theology, Asian theology, Feminist theology, etc.)