The wpcrmsystem_name_prefix filter controls the name prefixes that are available in a contact's record.

By default the prefixes include:

$args = array(
    ''=>__('Select an Option','wp-crm-system'),
    'mr'=>_x('Mr.','Title for male without a higher professional title.','wp-crm-system'),
    'mrs'=>_x('Mrs.','Married woman or woman who has been married with no higher professional title.','wp-crm-system'),
    'miss'=>_x('Miss','An unmarried woman. Also Ms.','wp-crm-system'),
    'ms'=>_x('Ms.','An unmarried woman. Also Miss.','wp-crm-system'),
    'master'=>_x('Master','Title used for young men.','wp-crm-system'),
    'coach'=>_x('Coach','Title used for the person in charge of a sports team','wp-crm-system'),
    'rev'=>_x('Rev.','Title of a priest or religious clergy - Reverend ','wp-crm-system'),
    'fr'=>_x('Fr.','Title of a priest or religious clergy - Father','wp-crm-system'),
    'atty'=>_x('Atty.','Attorney, or lawyer','wp-crm-system'),
    'prof'=>_x('Prof.','Professor, as in a teacher at a university.','wp-crm-system'),
    'hon'=>_x('Hon.','Honorable - often used for elected officials or judges.','wp-crm-system'),
    'pres'=>_x('Pres.','Term given to the head of an organization or country. As in President of a University or President of the United States','wp-crm-system'),
    'gov'=>_x('Gov.','Governor, as in the Governor of the State of New York.','wp-crm-system'),
    'ofc'=>_x('Ofc.','Officer as in a police officer.','wp-crm-system'),
    'rep'=>_x('Rep.','Representative - as in an elected official to the House of Representatives','wp-crm-system'),
    'sen'=>_x('Sen.','An elected official - Senator.','wp-crm-system'),
    'amb'=>_x('Amb.','Ambassador - a diplomatic official.','wp-crm-system')

The keys are what get stored in the post meta, and the values are what get shown on the edit form.