There are thousands of Vashikarana, Marana, Vidveshana and all kinds of mantras in the Tantras. In my own lineage, we are taught these are tools to know but rarely used. It is just that people have no familiarity with Sanskrit to read and understand the Tantras. I am also always weary of “this is secret” and hence no one knows kind of “mantras” because how does one verify its authenticity if no one other than the one marketing it claims to know it?
But Dhyan Guru’s mantras hardly seem to be authentic mantras “which are undergound” haha
The mantra of Kali in her calmer aspect is Kleem (‘l’ sound represents the earth and hence the grounded aspect of Kundalini).
The mantra of Kali in her aroused aspect is Kreem (‘r’ sound represents the fire and hence the awakened and blazing aspect of Kundalini) - this is also the form where she is in conjugal union with Shiva who grounds the energy.
The bija Kroom is potentially a “hand me down, missed in translation” mistake of Krom, which is the ankusha (goad) bija, used popularly for attraction, subjugation, etc.