Here are some ideas for Metaphysical or Spiritual Halloween costumes:
Time Traveler: Blend futuristic elements with pieces from the past. Carry a time-travel device of some kind to represent transcending time.
Divine Being: You could be a deity or mythical creature.
Elemental Being: Get inspired by the elements and dress as either earth, air, fire, or water.
Tarot Card Reader: You could wear a mystical outfit and carry a deck or Tarot cards. Or you could actually dress up as someone from the Tarot (High Priestess, Magician, etc.)
Ancestor Spirit: Honor an ancestor by dressing up as a spirit from the past.
Astral Traveler: You can do this in many ways. A futuristic outfit. A space suit. Attach a silver cord to you. Make it your own!
Celestial Being: Dress up as the moon, a star, or the sun. Glitter might be a fun addition here.
Witch: I've been Pagan for a long time and this one can be controversial. Some witches take offense to the stereotypical "witch" costume, and others don't care. But it's an easy option that can be fun if you're comfortable with it.
Definitely let me know in the comments if you've ever dressed in a Metaphysical or Spiritual Halloween costume.
Have a great weekend and many blessings. - Veianya