You can recite mantras on any of the Seven Rays:
"Archangel Michael, Protect Me! Archangel Michael, Seal Me! Archangel Michael, Stand Where
"I AM Awake! I AM Awake! I AM Awake!"
"I and My Father Are One. I and My Mother are One."
"I AM Alpha and Omega in the White Fire Core of Being."
"I AM the Resurrection and the Life of my finances! (3x) Now made manifest in my hands and use today!"
"In the name of Jesus Christ: Peace, be still! In the name of Jesus Christ: Peace, be still! In the name of Jesus Christ: Peace, be still!
"I AM a Being of Violet Fire. I AM the Purity God Desires."
Om Wagi Shori Mum - increases the effectiveness of communication and in delivering the Word. The translation is “Hail to the Lord of Speech!” Manjushri is known as the Lord of Speech and the master of eloquence.
What Exactly Is a Mantra?
The formal definition of a Mantra from Saint Germain On Alchemy: Formulas for Self-Transformation by Mark and Elizabeth Prophet is:
"A mystical formula or invocation; a word or formula, often in Sanskrit, to be recited or sung for the purpose of intensifying the action of the Spirit of God in man. A form of prayer consisting of a word or a group of words that is chanted over and over again to magnetize a particular aspect of the Deity or of a being who has actualized that aspect of the Deity."
The ascended master Manjushri says, “If you choose to recite my mantras, I will assist you in coming to the oneness of the mind of God.” Two other Manjushri mantras are:
Om Ah Ra Pa Tsa Na Dhih is given to help develop wisdom, memory and the understanding of the scriptures. The final syllable, Dhih, is Manjushri’s bija, or seed syllable. The essence of a cosmic being is concentrated in his bija. The bija may be given alone or repeated as many times as possible after the final repetition of the mantra.
Gate Gate Paragate Parasamgate Bodhi Svaha invokes the wisdom of the Prajna-paramita scriptures and can also be given to Manjushri. It means “Gone, gone, gone beyond, gone wholly beyond—Enlightenment, hail!” or “Proceed, proceed, proceed beyond, proceed completely beyond—be founded in enlightenment!” This mantra can propel us beyond illusion and the illusory self into Reality and the Real Self.
 Manjushri, “You Have the Mind of God!” Pearls of Wisdom, vol. 37, no. 21, May 22, 1994.