I'm a month and a half late bringing Myroslava T. Znayenko's The Gods of the Ancient Slavs: Tatishchev and the Beginning of Slavic Mythology back to the NKU library. Before I drop it off, I might as well post something from it.
From the Primary Chronicle of Vladimir (980AD), we get that the primary pagan gods of Russia included Perun, the chief god; Xors Dazbog; Stribog; Simargl; and Mokos.
Other sources include Volos, god of animals; Pozvizd (called Poxvist in Poland), god of air; Lado, god of the underworld (like Pluto but cheerful) who was appealed to for success in marriage; Kupalo, god of abundance; and Koljada, "honored in evil ceremonies on December 24."
Later sources (Russia became Christian about AD 1000) began to include "new and improved" gods that probably were distortions or outright lies including Zuarasici, the new chief Slavic god; Jesza, equivalent to Jupiter; Lada, Mars; Dzidzileyla, goddess of marriage; Dziewanna, Diana; Nya, Pluto; Marzanna, Ceres; Pogoda, weather god;) and Zywie, God of life.
The worship of Norse/Germanic gods invaded Russia so devotions to Thor, Wotan, and Frikko (god of peace and pleasure) were common, particularly in the west.
Some of the old gods were incorporated into Orthodox beliefs but nowhere near the extent that the Irish converted old gods into Catholic saints. Devotions to the spirit world (leaving food and milk to supernatural creatures) was well documented before the Russian Revolution and some of the stories still survive in modern folklore.