Spells that won't offend what gods and goddesses? The celtic ones? If so, may I suggest a book? It's called "Celtic Devotional Daily Prayers and Blessings" by Caitlin Matthews. While it isn't spells, per se, it will give you an idea of the direction you want to go in, I think. The prayers work for me and I haven't offended anyone yet, even though I've been using those prayers for over five years.
Could someone who knows Celtic myths and gods, please help me with a dedication to the Morrigan. I am trying to set it up for Samhain but I am having trouble finding spells and rituals pertaining to The Morrigan.