Dark Navy Blue or Charcoal Grey: Excellent, respectful alternatives if you do not own appropriate solid black clothing.
Subdued Earth Tones: Muted olive greens, deep burgundies, or dark browns are generally acceptable as long as the garments are modest and conservative.
Ultimately, the goal of funeral attire is to blend in respectfully, allowing the focus of the day to remain entirely on honoring the memory of the person who has passed.