Yogi Bhajan used to advise us to rely on St. Anthony to help find lost things, and I have always had good luck with this.
He learned this when in Catholic school in India as a boy!
Anthony, Saint Anthony please come down. Help (your name) find what can't be found! (Then name what you are hunting
The following mantra is one that Yogi Bhajan taught in later years.
It calls on the third and fourth Sikh Gurus to send your prayer, and it is quite effective. This is a "transliteration"
of Gurmukhi mantras so that it retains its original, powerful sound current.
"Guru Amar(a) Guru Siri Saat - Kalijug(a) Rakhi Paat"
Raj Jog Takhat Dheean Guru Ram Das
"Ardas Bhaee Amardass Guru Amardass Guru
Ram Das Guru, Ram Das Guru, Ram Das
Guru, Sachee Sahee."
Yogi Bhajan said that the latter must follow the initial
phrase to "seal" the result.