A few examples that serve well textually are the Charmer’s Psalter by Gemma Gary, the Carmena Gadelica (not witchcraft proper but traditional fairy faith folk magic), Kitchen Witch by Cora Anderson, and the Book of Gold (among many grimoires of the medieval and early modern periods like the Key of Solomon to use psalms—used by sorcerers of many sorts including cunning folk and witches). In all of these Psalms of various kinds calling on Mary and the Trinity are used far outside their general Christian context. Yet they call on or command the same literary powers seemingly.
Some of the above links refer to full texts or excerpts and others to introductory material highlighting the historical importance of psalms. I would have to say the most instructive link is for Kitchen Witch, Cora who died very recently is a traditional witch of the fairy faith persuasion and one of the three founding members of Feri an American Fairy Faith Traditional Witchcraft lineage. She includes practical details on how she used the psalms for spell work to successful ends.
My teacher, Grayson Magnus, likes to say, its our Bible too! Referring to the concept that really witchcraft as a heresy was defined and created by various biblical edicts and cemented in the King James translation that held over much of our darker times. You can translate that one verse many ways, but when it comes down it if you say Sorceress, Poisoner, or Witch—all three fall under the auspices of witches who throughout history make the use of various ethenogenic plants (as mild as frankincense to as deadly as the hemlock included in many medieval flying ointment recipes) risky as right down to the Woman from Endor who lit a smokey incense when she called on the dead for answers; cast spells and use divination as sorcerers and sorceresses and after a certain point in history were tried as witches by the power invested in kings by god’s rite of succession “secular-ally” in government courts or by the inquisition in religious courts. You can see how Cora reacts to that, she likes some parts of the bible and uses them and magic and rejects others because she sees them as put in for social reasons.
Its a difficult paradox for pagan witches—some of our ancestors (like Cora for example) were Christian, yet quite heretical in their approach. Victor Anderson (the main founder of Feri) said that all gods were Feri gods—and its hard sometimes to know quite what he meant. But knowing that Mari and Nimue and Dian-Glas and so many other gods are of the higher importance in Feri, I am pretty sure they held other gods before Jehovah. And that is where the clincher is, a Witch generally will work with gods (like the Terry Prachett quote, they don’t believe in them, they know them too well for that—that’s like believing in the postman)—but they don’t follow them. They don’t bow down to them. They don’t rely on them. Generally witches have their own personal gods that are in a way part of themselves. And generally witches rely on themselves. But if they can call on Mary or the Trinity or any number of other powers, they will because they have the strength and power to call and be answered.