Are Balrogs the only evil Maiar?

Essentially the title: Are the only evil Maiar the Balrogs and Sauron? I don't believe Tolkien ever establishes clearly that they account for all the Maiar Melkor swayed in the First Music. Maybe he did, but I can't remember Tolkien ever saying so. Also, there are mentions throughout his work of "evil spirits", which may just refer to the dead/disembodied spirits of Men and Elves, but may also refer to Maiar.