What are the supplications that can be used for marriage to a specific person after being impressed by their personality, without prior acquaintance?

If the suitor is a person of religious commitment and good character, one can perform the Istikhara prayer. If there is good in him, Allah will facilitate it, and if not, He will divert him. There are no specific supplications for this matter other than the Istikhara supplication itself. One can supplicate with whatever achieves the purpose, and one can also subtly present oneself to him.