The unfruitful works of darkness are: covetousness, perversity, fornication, idolatry, rioting, drunkenness, lewdness, lust, jealousy, arguing, fighting. The unfruitful works of darkness are inward (heart) conditions. It's walking in the flesh and not in the spirit of Christ Jesus.
If we want to get technical,
every single holiday we celebrate in modern society originated from pagan roots. Christmas, Easter, Thanksgiving & Halloween. Even the way people celebrate birthdays, anniversaries, weddings, and funerals generated from pagan rituals.
Also, there's numerous insects, animals, and aspects of nature (owls, cats, locusts, frogs, cows, trees, the sun, the moon, etc) that have been either worshipped and/or believed to be accursed. People will idolize movie stars, popular singers & musicians, billionaires, sports icons, legendary authors, distinguished scientists, famous politicians, etc.
Paul even pointed out that many people were beguiled by religious leaders who spoke with “excellent speech and persuasive words” of so-called wisdom. Many people flatter these religious leaders and exalt them over others because they’re convinced they’re more deserving of praise by their flowery speech and popularity.
In other words, there isn't much under the sun that's not been corrupted and defiled by carnal man. You'd be hard pressed to find a holiday celebration that doesn't have roots in carnality.
Nevertheless, Jesus attended a wedding celebration in Cana and not only turned water into wine, but drank it. So what does that tell us? "To the pure, everything is pure."
We are in this world, not of it. We can't reach the lost if all we do is point our finger at everything and proclaim it’s demonic like anxiety-ridden fanatics. That is insane. Romans 14:14 tells us, “I am convinced, being fully persuaded in the Lord Jesus, that nothing is unclean in itself. But if anyone regards something as unclean, then for that person it is unclean.”
We can perceive anything evil when we take our eyes off the light of God and focus on darkness. This is our Father's world and everything that's in it.
We can celebrate any holiday so long as we do everything as unto the Lord. That is, do all with a joyful heart in Christ Jesus and treat others the way we want to be treated: with love and acceptance, as Jesus treats us.
Of course, there are boundaries and we shouldn't give ourselves over to lack of self-control. But instead of freaking out in anxiety and condemning everything because it might have roots is paganism, ask God for wisdom and trust him to guide you in all things.
If someone doesn’t want to celebrate Halloween, they shouldn’t celebrate it. If someone else has peace about it, then they should celebrate it. It's that simple.