Codes of Slavic Cultures: The journal Codes of Slavic Cultures is devoted to the traditional spiritual culture of the Slav peoples.
Eastern Slavic Reflections on Nature: An account of how, the Eastern Slavs, particularly the pre-Christian Russians, interacted with nature.
Moist Mother Earth: Slavic Myth and Religion, Slavic Gods, and rituals.
Slavic Goddesses: Directory of Slavic Goddesses from Wikipedia.
Slavic Gods: Directory of Slavic Gods from Wikipedia.
Slavic Religion: Slavic mythology and Slavic religion evolved over more than 3,000 years. It's conjectured that some parts of it are from neolithic or possibly even mesolithic times. Wikipedia article.