My favorite is Bog king from Strange Magic - Has a song talking about how evil he is. But all he does is prevent the spread of dangerous mind control magic, and quarantine people under the effects of said magic. Yes he greatly annoys people doing so, but honestly? If I get hit by a love potion, please quarantine me.
Different character, but there is a lot of overlap. When the show introduced Crowley for the first time, I thought it was an omage to Good Omens.
You guys know about the actual occultist Crowley, right?