Below are prema mantras categorized by the Personality the mantra calls on.

You can listen to all the mantras shown below here.

Addressing Radha and Krishna

hare krishna, hare krishna, krishna krishna, hare hare

hare rama, hare rama, rama rama, hare hare

Addressing Krishna

govinda jaya jaya gopala jaya jaya, radha ramana hari govinda jaya haya

he govinda he gopala, keshava madhava dina dayal

om sri krishna sharanam mama

om sri krishnaya namah

om tad visnoh paramam padam

om tat sat

klim krishnaya govindaya gopijana vallabhaya svaha

klim krishnaya vidmahe damodaraya dimahi tano deva pracodayet

om namo bhagavate vaasudevaya

Addressing Radha

srim radhaya svaha

srim radhikayai vidmahe prema pupaya dimahi tano radha pracodayet

Addressing Sita-Rama

om sri rama, jaya rama, jaya jaya rama

om sri rama namah

om sri rama saranam mama

om sri sita-rama saranam mama