Specific fine arts-related databases:
More general databases that provide scholarly resources in art history and the humanities:
Reference sources (encyclopedias, dictionaries) are useful for gaining a broad understanding of a topic, gathering important dates, names of people, timelines, and more. This is a great place to start your research.
Dissertations and Theses are unpublished scholarly works that can provide extremely useful in-depth looks into specific topics in art history. They are also useful for starting your research, as they often contain comprehensive literature reviews and are useful for discovering resources on your topic.